22g High EAA (6g) Protein + 36g CHO Pre- / Intra-Workout Boost Fat Oxidation & PWO Resting(!) Energy Expenditure

I don't doubt that you can do that, too!

It does sound awkward: If you mix Twinlab: Amino Fuel (22 g protein - 6 g essential amino acids | L-phenylalanine: 633 mg; Lvaline: 781 mg; L-tryptophan: 133 mg; L-threonine: 679 mg; L-isoleucine: 565 mg; L-methionine: 292 mg, L-histidine: 282 mg; L-leucine: 1350 mg; L-lysine: 1449 mg) with a regular  sports recovery drink that contains 36g of simple sugar, down half of the resulting 800ml serving of whatever you want to call this mix immediately before your workout and consume the rest during the rest periods between sets, this will have measurable effects on your resting energy expenditure and fat oxidation.

From long-term to short time effects

At first, it does questionably sound counter-intuitive that the ingestion of an EAA + carbohydrate mixture before / during would increase the resting energy expenditure and rate of fatty acid oxidation after your workout. On the other hand, if you think about the long-term effects of corresponding supplement regimen, you don't have to look far, to find evidence that they can promote both, muscle gain and fat loss (Bird. 2006).

You can learn more about protein intake at the SuppVersity

Are You Protein Wheysting?

Cod protein for recovery

Protein requ. of athletes

High EAA protein for fat loss

Fast vs. slow protein

Too much ado about protein?

Kyle J. Hackney, Andrew R. Kelleher, and Lori L. Ploutz-Snyder from the Syracuse University speculated that the highly beneficial changes in body composition Bird et al. observed in their study participants over the course of a 12-week strength training + EAA & CHO supplementation that after "[t]hese adaptations may be related to the acute energy expenditure and substrate utilization responses in the postexercise period." (Hackney. 2013)

Figure 1: The changes in body composition (in kg) in response to 12 weeks of resistance training + placebo, CHO, EAA or CHO + EAA supplementation in 2006 study by Bird et al. "inspired" Hackney et al.

Against that background, it was only logical to conduct a study to examine how multiple bouts of resistance exercise with and without the strategically timed intake of amino acids affect the resting energy expenditure (REE) and respiratory exchange ratio (RER). The results could after all explain if the long/er) term effects on body composition that have been observed in previous studies using chronic training and supplementation regimen are maybe nothing but necessary consequences of repeated acute increases in REE or decreases in RER (you hopefully remember that a decrease in the respiratory exchange ratio signifies an increase in fatty acid oxidation).

Experimental design and results

To this ends, the researchers recruited 10 young (mean age: 23.4y) recreationally trained male participants. All of them had been participating in general resistance training exercise for a minimum of 3 days per week for at least 6 months.

Figure 2: Changes in resting energy expenditure (kcal/day) and comparison of training volume in 58g CHO (black bars) and EAA + CHO (white bars) trials (Hackney. 2013).

As you can see in Figure 2, Hackney et al.'s original hypothesis that "intake of amino acids with each resistance exercise session would lead to greater perturbations of REE and RER" (Hackney. 2013) does unquestionably hold for this population of average (rookie) gymrats.

Whether the scientists "main finding" (Hackney. 2013), i.e. the 3.61% increase in resting energy expenditure (REE) will be similarly pronounced in advanced trainees is yet as questionable as the real-world effects of this artificial value. Despite the fact that Hackney et al. are right, when they say that our resting energy expenditure "represents the largest component of [our] total daily energy expenditure (60–85%) and has been implicated as a major contributor to overall body mass management " (Hackney. 2013), I am not sure how "major" an increase of only 66kcal per day actually is... I mean,  if this pathetic increase in resting energy expenditure was the actual driving force we would need almost 100 days to shed a hilarious pound of body fat (note: the reason I use the flawed 3,500kcal = 1lbs of fat rule of thumb here is that the whole REE calculations would be pointless if you didn't put at least some faith into the "energy in vs. energy out" hypothesis of weight loss - right?)

SuppVersity Suggested Read: "Fat Loss Principles That Work: 10g+ of EAAs W/ Every Meal. Do Energetic Costs of Protein Synthesis Trigger This Effect?" |  read more

Bottom line: It stands out of question that your training success can benefit from a high EAA protein source and some carbs you consume before and during the exercise session. Whether the fat loss benefits are actually brought about by the marginally increased resting energy expenditure (REE) is yet something I doubt - it certainly helps fat loss, but clearly isn't its main motor.

Don't get me wrong, this does not imply that you will benefit from this type of "peri-workout" supplementation. And let's be honest, the end most of you probably don't care about the exact underlying mechanisms, as long as your body composition keeps improving, right?

References:

• Bird, S. P., Tarpenning, K. M., & Marino, F. E. (2006). Independent and combined effects of liquid carbohydrate/essential amino acid ingestion on hormonal and muscular adaptations following resistance training in untrained men. European journal of applied physiology, 97(2), 225-238.
• Hackney, K. J., Kelleher, A. R., & Ploutz-Snyder, L. L. (2013). Amino Acid-Carbohydrate Intake Combined with Multiple Bouts of Resistance Exercise Increases Resting Energy Expenditure. ISRN Nutrition, 2013.

Dairy Protein Shoot-Out: Intact Casein, Casein Hydrolysate, or Whey, What's the Most Satiating Protein and Boosts Fatty Acid Oxidation Most Effectively? And What Does it Imply?

I doubt any of the shakes the subjects consumed looked that delicious!

If you click on "protein supplements" on the website of any Internet supplement vendor, it will be quite obvious that dairy proteins dominate the supplement market. For a good reason! They are easily digested, taste good and have a ton of research to back their superior efficacy as potent muscle builders (Hulmi. 2010).

If you look closer, you will realize that whey proteins are mostly marketed as fast-digesting post-workout muscle builders, while casein proteins, which have a much lower market-share, are said to be slow digesting or even "time-released" proteins that promote long-lasting anabolism and satiety.

Learn more about the effects of your diet on your body composition at the SuppVersity

Dieting Makes Gymnasts Fat!

Minimal Carb Reduction, Max. Results?

HIT Circuit + Plyos for Glucose Management

How Much Carbs Before Fat is Unhealthy?

5 Tips to Improve & Maintain Insulin Sensitivity

Carbohydrate Shortage in Paleo Land

If you've been around for quite some time, you will know that this is generally true, but the cheap caseinates (calcium or sodium), or casein hydrolysates are not exactly "slow" digesting.


Against that background the results of a recent study by scientists from the University of Copenhagen, the National Institute of Nutrition and Seafood Research in Bergen, Norway, and the Bispebjerg Hospital in Copenhagen could be particularly enlightening, because they could help us determine the "best protein" for particular purposes.

In said study, Line Q. Bendtsen and her co-workers compared the effects of hydrolysed casein, intact casein (calcium caseinate) and intact whey on energy expenditure (EE) and appetite regulation in order to find out, whether and how the amino acid composition and the rate of absorption affect these parameters.

"On the basis of the expected differences in absorption rates, we hypothesised that whey and hydrolysed casein would be more satiating and have a greater effect on EE shortly after protein consumption, whereas intact casein would be more satiating and have a greater thermogenic effect several hours after protein consumption." (Bendtsen. 2014)

In addition, the scientists hypothesized that whey would have a more satiating effect than hydrolysed casein due to its higher protein quality. Now, this is obviously something that would go against the previously formulated general rule of thumb that casein (no matter which type) was the most satiating dairy protein... but hey, we'll see.

We're not talking about lean athletes, here: As a SuppVersity Reader you know that science can be a bitch and getting financial support for your research usually requires using overweight or older subjects (who cares about young men and women who want to look good naked ;-). It will thus not come as a surprise that the subjects of the study at hand were thirty-six healthy, but overweight to moderately obese (BMI: 27 – 35 kg/m²) men and women aged 22 –40 years and thus not exactly representative of the average physical culturist. We will get back to the potential implications in the bottom line, but I wanted to point this out right away, for you to be able to put the study outcomes into the right perspective.

After the "bad news" in the red box, there is yet also "good news" which is the fact that the researchers used a "metabolic chamber" and thus a pretty accurate method to determine the exact effects on energy expenditure and fatty acid oxidation in response to the ingestion of ~30g (3g/1MJ energy intake) of supplemental protein (HC, IW or IC) in liquid / shake form. Each of the shakes the participants ingested on three seperate conditions contained 26 E% [energy percent] from protein, where hydrolized casein (HC), intact whey (IW) and intact casein (IC) contributed to 22.3% of the total energy in the respective shakes.

Table 1: Amino acid composition of hydrolysed casein (HC), intact casein (IC) and intact whey (IW) - Single free amino acids (Leu, Phe, Pro, Trp and Tyr) were added to HC to match the amino acid composition of IC (Bendtsen. 2014).

Table 1 summarizes the exact amino acid composition of the three shakes on a milligram per gram base. As you would have expected the whey protein shake contained a significantly higher amount of BCAAs (leucine, isoleucine, valine), but lower amounts of glutamic acid / glutamine, arginine and phenylalanine compared to the two casein proteins.

To assess the appetite of the subjects who received identical diets on day 1 of all three occasions (breakfast 26E% from protein, 50E% from CHO and 24E% from fat | lunch 18E% protein, 57E% CHO and 25E% fat | dinner 17E% protein, 58E% CHO and 25E% fat) and had ad libitum access to water, the scientist used a classic visual analogue scale.

So, what's the best protein then? There is no single best protein, but as I have outlined in previous articles, the combination of whey and micellar casein at ratios of 30:10 and 10:30 mark the extremes you can use to induce a pro-anabolic state of hyperaminoacidemia post-workout (immediate sustained elevations of amino acids) and pre-bed (long-lasting elevation of amino acids), respectively | learn more and even more about the "ideal" protein mix.

In addition, the ad libitum intake on the lunch the subjects were served on day two (spaghetti Bolognese | 15 E% from protein, 55 E% from CHO and 30 E% from fat) after a protein shake only breakfast was recorded as a measure of the real-world relevance of potentially differential effects of the three types of protein on appetite ratings.

Figure 1: Experimental design. All twenty-four subjects made three visits during the study period (Bendtsen. 2014)

I know that's quite complicated, but I guess the graphical overview in Figure 1 is going to help you to understand the exact procedure and timing. Right? Ok, then let's take a look at the results:

Figure 2: .Substrate oxidation during daytime (A) and after the breakfast meal (B) on day 1 (Bendtsen. 2014).

• There was no differences in 24 h and postprandial energy expenditure or appetite regulation.
• The estimated lipid oxidation (based on the respiratory quotient (RQ) that was measured in the metabolic chamber) was found to be increased after consumption of intact whey (IW) and hydrolyzed casein (HC) during daytime (P < 0.014), but not after the ingestion of intact casein (IC).
• The concentration of non-esterified fatty acids (NEFA) in the blood of the subjects was found to be higher after consumption of intact whey than after consumption of either form of casein (P < 0.01). 
• The concentrations of insulin or glucagon-like peptide 1 (GLP1 | learn more) were identical in all three conditions.

In other words, the effects on energy expenditure and appetite regulation do not differ significantly between the three types of protein. If anything, the "fatty acid oxidation advantage" of whey may be something to keep in mind - specifically, if you don't depend on the long-lasting hyperaminoacidemia (elevated and thus pro-anabolic amino acid levels) in response to the ingestion of intact casein.

There is another "hidden" problem: The "intact" casein used in the study is not intact. It's Miprodan (R) a calcium caseinate and thus a fast digesting, some would say "inferior" form of casein (compared to micellar casein). It's thus not surprising that there were no differences in the insulin response to whey and no wonder that the "regular" casein placed last in the comparison - another good reason not to overrate the results of the study at hand.

Bottom line: Overall the differences are probably too small to use them as a basis for your decision for or against a specific form of protein. If you look at the graphs in Figure 2, the most important message for the average gymrat probably is that the recently hyped casein hydrolysates are probably not worth it. With an inferior amino acid composition (compared to whey) and similar fast absorption kinetics as intact whey isolates, there is no real reason to chose them over the alpha male among dairy proteins: Whey!

It is furthermore unlikely that having normal-weight or athletic subjects would have changed the results much. As you've learned in a recent SuppVersity Article, the thermogenic effect in response to food is blunted in overweight / obese individuals, but that's a disadvantage, all three forms of protein had to deal with. It's thus unlikely that using lean subjects would have had a major effect on the overall (allegedly rather disappointing) outcome of the study | Comment on Facebook!

References:

• Bendsen et al. "Effects of hydrolysed casein, intact casein and intact whey protein on energy expenditure and appetite regulation: a randomised, controlled, cross-over study." British Journal of Nutrition (2014). Ahead of Print.
• Hulmi, Juha J., Christopher M. Lockwood, and Jeffrey R. Stout. "Review Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein." (2010).

Organ Specific Resting Metabolic Rates and Diet-Induced "Metabolic Damage". Plus: At Rest Heart, Liver & Kidney Consume 83x More Energy/kg Organ Mass Than Muscle

No, your muscles are not the primary gas guzzler in your body.

The problems arising as a consequence of a diet-induced reduction of the metabolic rate are among the recurring themes here at the SuppVersity. For a good reason, as I would say. After all, they are the #1 reason for weight loss plateaus and the yoyo effect. Although the notion that "calories count" is not very popular these days there is no debating that an energy deficit is a necessary prerequisite for weight loss. The problem however is that you cannot determine your energy balance with a calculator, a body fat caliper and a scale. There are way too many other factors involved - the amount, macro- and micronutrient composition, timing, frequency, volume, texture and palatability of the ood you eat, stress, hormonal factors, etc - all of which will affect the amount of energy you expend and subvert the results of over-simplistic calories-in vs. calories-out calculations.

What are the most notorious gas guzzlers in our body?

Things would actually already be complex enough, if we focused solely on that "input" <> "output" recursion, but unfortunately, even the notion of a "global" (=valid for the whole body) metabolic rate is nothing we can really rely on. If we wanted to have a somewhat more accurate estimate of our basal energy requirements, i.e. the amount of energy we need if we don't move all day (which is basically what the average Westerner does, these days ;-), we would have to know the individual energy requirements of all our major organs and add them up, using a formula like this:

The more you eat, the more you burn. You can find more evidence that men & women are no bomb-calorimeters here

240x brain mass in kg

+ 440x heart mass in kg
+ 200x liver mass in kg
+ 440x kidney mass in kg

+ 13x skeletal muscle mass in kg
+ 4.5x adipose tissue mass in kg

+ 12x residual mass in kg

This formula, which was developed based on studies of Elia et al. in 1998, assumes that the metabolic activity of an organ increases linearly with its mass and that the specific metabolic rates (ki-values, i.e. 240 for the brain, 440 for the heart, etc.) are accurate. In the average, normal weight non-dieting individual these values are constant and have been confirmed lately in a set of experiments that were conducted by Wang et al. (see figure 1)

Figure 1: ki-Values of adipose tissue, skeletal muscle, liver, brain, heart, kidneys, residual volume from the Wang studies; all values expressed relative to the reference values from Elia (1998)

These studies, which were published subsequently in 2010, 2011 and 2012, also reported that there are distinct trends for decreasing ki-values and thus lower resting energy expenditures at identical organ masses in both obese / lean and older / younger individuals - an effect which can be explained by either lower cellularity or lower specific metabolic rates of the respective organs and tissues. In light of the fact that the "organ weight x ki-value"-calculations are very accurate and that

"there is only a small and nonsignificant difference between REEm [measured resting energy experience] and REEc [the energy experience calculated based on ki-values and organ masses] of about 13 to 80 kcal/day" (Müller. 2013b)

it should be obvious that both aging and already being obese put you at a higher risk of weight gain in a society where energy dense foods and large portion sizes are the rule, not the exception.

Is there something like organ specific metabolic damage?

A couple of recent studies have investigated the effects of weight loss and regain on organ-specific energy expenditure in order to find out if this may be the, or at least one of the underlying reason for the reduced resting energy expenditure in formerly obese individuals (Müller. 2013a; Bosy-Westphal. 2009 & 2013). These studies support the idea of a fall in the organ size and weight and the corresponding ki-values of high metabolic rate organs (heart, kidney, liver) with weight loss. Bosy-Westphal (2009), for example report a -136kcal/day reduction in resting energy expenditure (REEm = measured) with 4-6% loss of liver, heart and kidney mass in obese women after 9.5kg body weight loss (2.6% fat free mass).

Figure 2: Difference between measured and calculated energy expenditure in MJ/day at baseline, after weight loss and regain in  47 obese men and women who lost 12kg (weight stable) and 9kg (weight regainers) in a study by Bosy-Westphal et al. from 2013

"In addition, the effect of weight loss and weight regain over a longer follow-up period of 6 months had been studied in 47 obese males and females (Bosy-Westphal. 2013). There were considerable differences between weight-reduced/weight-stable individuals compared with weight regainers. Over a period of 6 months, weight-reduced/weight-stable individuals had lost 12 kg body weight, the weight change-associated changes in the REEm - REEc values were 33 and 45 kcal/day, with initial weight loss and with long-term follow-up (i.e. between 12 weeks and 6 months). By contrast, weight regainers regained 6.3 kg body weight after an initial loss of about 9 kg. The corresponding data on the weight changeassociated changes in the REEm - REEc values were 69 and 10 kcal/day, respectively. Individual data for the group ‘regainers’ at basal before and after weight loss, as well after weight regain, are shown in [figure 2]. The changes in the REEm- REEc values argue for changes in specific metabolic rates with weight changes." (Müller. 2013b)

What? Ok, I have to admit that this paragraph from Müller's 2013 review of the literature is not actually easy to understand. So let's take a look at the data in figure 2 again. The main message here is that the weight loss narrows the natural spectrum of REEs down to the minimal requirements of your organs. In other words, the body is running on low fumes and is thus particularly prone to weight regain which can - but does not have to - lead to an increase in the per pound organ weight energy expenditure that would then become obvious in the form of a larger difference between the measured (REEm) and calculated (REEc) resting energy expenditure (green and red circles in figure 2). With the pre-post weight regain difference being 69 vs. 10, it is yet unfortunately more common that the initial organ energy expenditure is not being restored (red circle in figure 2) and the energy expenditure remains low although people regain a lot if not all of their weight.

---

Suggested read: "Do Chronic Energy Deficits Make Athletes Fat? The Longer & More Severe You Starve, the Fatter You Are. Irrespective of What the Calories-in-VS-Calories-Out Formula May Say" | read more

What can you do with this information? Not that much, I have to admit. If anything the major contribution of non-muscle tissue to the diet induced reduction of the resting metabolic rate should remind you that it may be at least equally important to spare the mass of the organs in your splachnic bed as it is to maintain as much lean muscle tissue as possible when your dieting.

I don't know if you remember the recent study about citrulline and it's effect on the maintenance of muscle and visceral tissue mass (see figure 1 in the respective article) or previous SuppVersity posts on other non-essential amino acids, such as glutamine or arginine? All of them are primarily "organ food" and an adequate provision of these conditionally essential amino acids should be considered as important as the provision of the purportedly muscle-protecting BCAAs if you want to keep the loss of organ mass at a minimum and your resting metabolic rate up. Whether and how you can influence the individual metabolic rate, of these organs is yet a totally different question to which no one has found a definitive answer, yet.

References:

• Bosy-Westphal A, Kossel E, Goele K,et al. Contribution of individual organ mass loss to weight-loss associated decline in resting energy expenditure. Am J Clin Nutr 2009; 90:993–1001.
• Bosy-Westphal A, Schautz B, Lagerpusch M,et al.Effect of weight loss and regain on adipose tissue distribution, composition of lean mass and resting energy expenditure in young overweight and obese adults. Int J Obes 2013.
• Elia M. Organ and tissue contribution to metabolic rate. In: Kinney J, Tucker HN, editors. Energy metabolism: tissue determinants and cellular corollaries. New York: Raven Press; 1992. pp. 61–79
• Müller MJ, Bosy-Westphal A. Adaptive thermogenesis with weight loss in humans. Obesity 2013a; 21:218–228.
• Müller MJ, Wang Z, Heymsfield SB, Schautz B, Bosy-Westphal A. Advances in the understanding of specific metabolic rates of major organs and tissues in humans. Curr Opin Clin Nutr Metab Care. 2013b Sep;16(5):501-8.
• Wang Z, Ying Z, Bosy-Westphal A,et al.Specific metabolic rates of major organs and tissues across adulthood: evaluation by mechanistic model of resting energy expenditure. Am J Clin Nutr 2010; 92:1369–1377.
• Wang Z, Ying Z, Bosy-Westphal A,et al.Evaluation of specific metabolic rates of major organs and tissues: comparison between men and women. Am J Hum Biol 2011; 23:333–338.
• Wang Z, Ying Z, Bosy-Westphal A,et al.Evaluation of specific metabolic rates of major organs and tissues: comparison between nonobese and obese women. Obesity 2012; 20:95–100.

Losing Weight Doesn't Have to Ruin Your Metabolism: No Unexpected Reduction in Energy Expenditure With Sane Weight Loss. Plus: 9 Simple Rules Every Dieter Must Follow

Weight loss is easy, but doing it fast and without losing muscle is - as of now - more of an art than a science.

In the past weeks I have received a couple of questions which revolved around the notion of diet and exercise induced metabolic shutdown. Although I'd hope that I did answer all your questions more or less to your personal satisfaction, I hope that taking the publication of two very recent papers as an incentive to write a whole article about this complex topic will spare me future lengthy elaborations on what exactly happens, when an obese, overweight or lean person reduces his body weight.

➲ Fast forward to the 9 simple rules if you're in a hurry

Before we are going to take a look at the ahead-of-press publication of a related review in the Journal of the International Society of Sports Nutrition, though, I want to briefly envoke the results a group of researchers from the Christian Albrechts University in Kiel presents in their latest paper in the American Journal of Clinical Nutrition (Pourhassan. 2014).

In the corresponding experiment, Maryam Pourhassan, Anja Bosy-Westphal, Britta Schautz, Wiebke Braun, Claus-C Glüer, and Manfred J Müller investigated the changes in body composition that occur, when overweight individuals lose weight and assessed their impact on resting energy expenditure and insulin resistance. As Pourhassan et al. point out,

Little has previously been known about metabolic effects of changes in the composition of either FM or FFM with weight loss and gain." (Pourhassan. 2014)

This is problematic. It should after all be self-evident that the changes in fat mass (FM) and fat free mass (FFM) and their ratio alone will have a significant impact on the resting energy expenditure (REE) of the dieter.

The interaction between "weight loss", energy requirements and health is a very complex issue, one that's unfortunately still "underinvestigated"

If we also take into consideration that the position of the fat stores, e.g. extremities vs. trunk, will have a major impact on the weight loss related improvements in glucose and lipid metabolism, as well as whole body inflammation, leptin, adiponectin and the production and effects all sorts of other crucially important proteins and hormones, it becomes obvious that the current practice of plugging, body weight, height and age into a formula and hitting the "="-key on your calculator cannot be exactly the ideal solution. And what's more, the fact that the changes in weight and the corresponding metabolic adaptations will recursively influence each other doesn't make the situation simpler, either.

Figure 1: Changes in glucose and insulin response during oral glucose tolerance test after diet and/or exercise induced weight loss (Dengel. 1996)

"Metabolic adaptations are a result of changes in body composition and variations in the metabolism of individual body components. Weight loss had a strong effect on improving insulin resistance in overweight and obese individuals (Dengel. 1996; Niskanen. 1996).

What's still missing, though, is the

[...] determination of whether metabolic effects of weight loss result from the reduction of specific fat depots (eg, in VAT) or a generalized decline of adipose tissue" (Pourhassan. 2014).

Studies like the one by Dengel et al. (see Figure 1) also provide initial evidence that exercise and diet induced improvements in body composition will have different effects on glucose metabolism, which is unquestionably one of the contemporarily most important health markers (and most common reasons people are unhealthy). Significant improvements of the blood glucose response to an oral glucose tolerance test, for example cannot be achieved solely by exercise. Only a reduction in body fat (and as I would suspect liver and muscle glycogen stores) as it is brought about by negative energy balances will get this job done.

In previous studies, the scientists from the Christian Albrechts University in Kiel have already been able to show that weight loss–related changes in FFM were mainly explained by a reduction in skeletal muscle mass (MM), whith a minor contribution of losses of kidney and liver mass. It goes without saying that the latter depends on the original weight of the organ and can be quite pronounced, in obese individuals, with beginning for full-blown NAFLD (Bosy-Westphal. 2013).

This is what the researchers did

In the study at hand, in the course of which 83 healthy subjects - 50% of them obese, the rest normal to overweight - were investigated at 2 occasions with weight changes between -11.2 and +6.5 kg (follow-up periods between 23.5 and 43.5 mo). At both visits to the lab, the scientists measured the...

• body composition by using the 4-component model and whole-body MRI
• resting energy expenditure (REE),
• plasma thyroid hormone concentrations, and
• insulin resistance

...by standardized methods to elucidate the associations between the changes in body composition, energy expenditure, thyroid hormone levels and glucose metabolism.

Yes, there was no dietary control: In the future it would be nice to see whether or not the means by which the study participants gained and lost weight correlate with the changes in body composition, thyroid hormone levels, resting energy expenditure and insulin sensitivity... the costs for an adequately powered study would yet be exorbitant, I guess.

If we take a look at the amount of muscle the weight losers dropped (-15%) and the -16% reduction in triiodothyronin (T3) and their relation to the accuracy of the calculated vs. measured energy expenditure in Figure 2, it may be surprising to see that the difference between calculated and real energy expenditure of the subjects is comparatively small.

Figure 1: Changes in body composition, and thyroid hormones (left) corresponding before calculated (unadjusted) and measured REE levels in weight gainers, losers and stable subjects (Pourhassan. 2014).

In view of a lean-to-fat mass weight loss ratio of 0.26 and body fat reductions of up to 59.5% (not shown in Figure 2) in the particularly nasty trunk area, it is eventually not that surprising as it may initially seem that the ~11kg the "weight losers" dropped did not result in the often-talked about metabolic shutdown, we see so often in relatively lean individuals whose dream of a cover model physique turns into a nightmare of lifelong dieting.

Figure 3: Resting energy expenditure (x-axes) expressed as function of total body mass (left), and lean body mass of weight losers (middle) and gainers (right), respectively (Pourhassan. 2014).

The data in Figure 3 confirms what the previous remarks implied: It's the lean mass and not the total body mass (right) that determines the resting energy expenditure before and after weight loss (left) and gain (middle). Moreover, a detailed statistical analysis of the date revealed several in- and interdependent associations between the changes in body composition on the one hand, and those of resting energy expenditure, T3 levels and glucose metabolism on the other hand:

"In a first analysis, we included changes in FFM and FM as independent variables.
Changes in FM explained 22.8% of the variance in changes in REE(measured), and changes in FFM explained an additional 7.4% of the variance. In a second analysis, we added changes in individual components of FFM (ie, changes in skeletal muscle, bone mass, adipose tissue, heart mass, kidney mass, liver mass, and brain mass) and changes in FM as independent variables. Changes in skeletal muscle explained 29.8% of the variance in changes in REE(measured), and changes in FM explained additional 4.2%."

When changes in plasma triiodothyronine were also included in a third model, an additional increase in the proportion of the explained variance was observed (44.7%). Overall, the changes in skeletal muscle and serum triiodothyronine explained 34.9% and 5.3%, respectively, of the variance in changes in measured REE; and the inclusion of the changes in kidney mass brought about another 4.5% increase of the explanatory value of the scientists' mathematical model.

Significant associations were also observed between HOMA-IR, the classic the marker of insulin resistance, on the one hand, and subcutaneous trunk (r=0.62), and arm and leg fat (r = 0.46). What's quite intriguing, though is that similar correlations for the "bad" visceral fat were observed only in the weight gainers, while "the decrease in SAT of the arms [...]was the only fat depot decrease that was associated with a decrease in the HOMA index with weight loss (r = 0.45, P < 0.012).

Skinny arms and insulin sensitivity? That sounds strange!

It does not only sound strange, it should also remind us of the fact that all the previously discussed correlations are statistics based on a more or less (rather more ;-) uncontrolled investigation into the interactions of weight loss, energy expenditure and metabolic health we should not overestimate.

In fact, this is where paper #2 comes into play. As Eric T Trexler, Abbie E Smith-Ryan, Layne E Norton who focus on in their review of the metabolic adaptation to weight loss on the "implications for athletes point out, there is plenty of good evidence to support the hypothesis that the energy restriction that's necessary for (rapid) weight loss will induce a number of adaptations that serve to prevent further weight loss and conserve energy. Trexler et al. speculate that ...

"[...i]t is likely that the magnitude of these adaptations are proportional to the size of the energy deficit, so it is recommended to utilize the smallest possible deficit that yields appreciable weight loss." (Trexler. 2014)

Consequently, they recommend (just like I did in previous articles) to adopt moderate energy deficits (my suggestion: 20-30% of the habitual, not the calculated energy intake), knowing that it will not just decrease the rate of weight loss, but also minimize the unfavorable adaptations that challenge successful reduction of fat mass.  In conjunction with a high(er) protein intake of >25% of the total energy intake and (my suggestion) at least 30g of high EAA protein with every meal (e.g. dairy, eggs, fish, pork, beef, chicken, turkey, and pea-protein for the vegans) this will facilitate stepwise body fat reductions with minimal reductions in lean body mass and a bearable impact on athletic performance.

There is no "magic macronutrient ratio": Although I do believe that many of you have finally realized that there is no magic weight loss pill, the emails and messages I receive on a daily basis leave no doubt that even SuppVersity readers have been bamboozled by the "magic macro numbers" that are thrown around all over the Internet. If there is a number you should you should remember, it's "30" as in 30g of quality protein with every meal" (make it 20g for "snacks" and read my interview w/ Sean Casey for more information on this issue).

It is moreover imperative that you keep lifting heavy objects while you're dieting. As I have outlined in my article "Protein Intake & Muscle Catabolism: Fasting Gnaws on Your Muscle Tissue and Abundance Causes Wastefulness" (read it) the increase in dietary protein will keep the protein synthesis elevated. What it won't do, however is to battle the diet induced expression of catabolic muscle proteins (read more) and the inevitable drop in testosterone  and IGF-1, I wrote about only recently in my article "High Protein Diets Don't Counter Anti-Anabolic Effects of Low Energy Intake" (learn more about the hormonal sides of dieting).

Take home message for the physique oriented dieter

The following list of rules, which is based on the latest bro- and pro-scientific evidence is going to help you make the most of your next diet,

• stick to stepwise reductions of total energy intake - start with 15% and increase in 5-10% steps, whenever you hit a plateau
• if not absolutely necessary limit your energy deficit to max. 40% - if you hit a plateau, take two weeks off and begin dieting again, instead of running yourself into the ground 
• keep lifting heavy while you're dieting to minimize muscle loss - you can use bot inter- (e.g. 1x powerlifting, 2x higher rep bodybuilding or circuit training routines per week) as well as intra-workout periodization (eg. a heavy compound lift for 5x5 and auxiliary exercises for 3x10 reps and 4x15 reps)

• 

  Never work out to burn calories | learn why

  use your diet, and only your diet to generate an energy deficit - there is room for both high intensity interval and classic low intensity steady state (walking on an inclined treadmill) exercise, but it must not be done to "burn calories" (learn why) - unless, obviously, you actually want to feel miserable and accelerate the fal loss stalling adaptive reduction in energy expenditure
• increase in protein intake to >25% of total energy - as long as you stick to the "-40% max"-rule this should leave enough room for the "magic" 2x RDA (1.6g/kg) value of which a study by Pasiakos showed that it produces a better lean-to-fat mass loss ratio than a diet with 2.4g/kg protein (learn more)
• consume at least 30g of EAA-rich protein per meal - this will bring you up to the magic 10g of EAAs which have been shown to be associated with improved body composition in epidemiological studies (don't use isolated amino acids, instead - they are non-satiating and have inferior metabolic and protein anabolic effects)
• implement regular refeeds, whenever your total energy deficit is >25% - the refeeds will consist of a single day of 10-15% above maintenance energy intake with a focus on carbohydrates, and should be implemented once or twice a week; they are are believed "to temporarily increase circulating leptin and stimulate the metabolic rate" (Trexler. 2014) and will thus postpone the occurrence of weight loss plateaus 

• 

  The beneficial metabolic effects of veggies are mediated in parts by stretch receptor <> vagus nerve interactions in your gut (Rolls. 2002; de Graaf. 2011). These are reduced / absent if you juice or powder your veggies.

  fill yourself up with vegetables - except from a few "high energy" exceptions you can and should eat as many veggies as possible; aside from the tons of healthy vitamins and phytonutrients, the mere increase in food volume is going to have a major metabolic impact that goes way beyond an increase in satiety and cannot be achieved with powdered and is significantly reduced with juiced vegetables (you can still "juice", if you insist even waste money on greens supplements, but their benefits will never be up to fresh produce)
• avoid post-starvation obesity by working your way up to your habitual energy intake progressively - this is particularly important to avoid the formation of new fat cells (=adipocyte hyperplasia), which are currently believed to stick "forever" (=the cells whole life-cycle of ~10 years); neither the pizza and McDonald's diet, nor - and this is something most people tend to overlook - returning to the dietary habits that brought you into a situation, where dietary restriction became obligatory to get (back) in shape are feasible ways of eating after a diet; increase your energy intake in <5% steps every three days and watch the scale and your image in the mirror carefully to minimize fat gains (it's impossible not to gain a minimal amount of fat)

While all of these recommendations have anecdotal evidence (many of them from generations of fighters, bodybuilders and figure athletes), not all are "scientifically proven" - the procedure of reverse dieting, for example, sounds logical, it appears to work, but a study that would compare the changes in body composition on a slow "on-ramp" to those which occur, when you return to a whole-foods, junk-food free maintenance diet - ie. the litmus test for reverse dieting - has yet to be conducted.

Bottom line: In spite of the fact that the primary sources (Pourhassan. 2014 & Trexler. 2014) today's SuppVersity article is based on deal with totally different subject populations, i.e. obese sedentary vs. lean and athletic, the rules I formulated towards the end of the article can be used to optimize and sustain fat (not just weight) loss by all dieters from the Biggest Loser candidate, whose life depends on a 50% reduction to the (almost) shredded physique athlete who does not want to sacrifice his / her health and future physique for the one triumph that may bring him / her a pro-card in whatever division he or she may be competing in.

References:

• Bosy-Westphal, A., et al. "Effect of weight loss and regain on adipose tissue distribution, composition of lean mass and resting energy expenditure in young overweight and obese adults." International Journal of Obesity 37.10 (2013): 1371-1377.
• de Graaf, Cees. "Why liquid energy results in overconsumption." Proceedings of the Nutrition Society 70.02 (2011): 162-170.
• Dengel, Donalald R., et al. "Distinct effects of aerobic exercise training and weight loss on glucose homeostasis in obese sedentary men." Journal of Applied Physiology 81.1 (1996): 318-325.
• Niskanen, L., et al. "The effects of weight loss on insulin sensitivity, skeletal muscle composition and capillary density in obese non-diabetic subjects." International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity 20.2 (1996): 154-160.
• Pourhassan, Maryam, et al. "Impact of body composition during weight change on resting energy expenditure and homeostasis model assessment index in overweight nonsmoking adults." The American journal of clinical nutrition (2014): ajcn-071829. 
• Rolls, Barbara J., and Liane S. Roe. "Effect of the volume of liquid food infused intragastrically on satiety in women." Physiology & behavior 76.4 (2002): 623-631.
• Trexler et al. Metabolic adaptation to weight loss: implications for the athlete." Journal of the International Society of Sports Nutrition 11 (2014):7.