High Energy Flux, A New Determinant of Successful Weight Loss? Eat More, Train More, Lose More? Increased Resting Metabolic Rate & Satiety, Decreased Hunger While Dieting!

Always hungry? Can't lose weight? "Train more and eat more" (not less!) could be the solution.

A recent thesis from Rebecca Foright, highlights that a high energy flux state characterized by high daily energy expenditure (resulting from increased physical activity) with matching high energy intake (high calorie throughput) may attenuate the weight loss-induced energy gap by reducing hunger and ameliorate the otherwise diet-related reduction in resting metabolic rate.

Foright recruited recruited eleven obese study participants from the Colorado State University community and surrounding areas to test her "exercise more, eat more, lose more (easily)" hypothesis.

The enrollment criteria included: BMI between 30-43 kg/m², age 18-55 years, weight stable over the prior 12 months, desire to lose weight, and ability to exercise as assessed by electrocardiogram (ECG), resting blood pressure and a normal incremental exercise test to exhaustion with simultaneous ECG. Exclusionary criteria included: pregnancy or breastfeeding, smoking, use of medication known to affect appetite or metabolism (including but not limited to antidepressants and statins), or prior surgery for weight loss. In short, most of the participants were what we today call "healthy obese."
"The approach used in this study was a within-subjects cross-over experimental design to test the effect of high and low flux states following weight loss on resting metabolic rate and perceptions of hunger and satiety."

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The study protocol was divided into four distinct phases: (1) baseline testing phase prior to weight loss; (2) weight loss phase induced by a hypocaloric diet over the course of several months; (3) weight maintenance phase in which subjects were maintained at the reduced weight for 3 weeks; and (4) experimental phase in which measures were obtained of subjects’ resting metabolic rates, fasting and post-prandial perceived hunger and satiety, fasting and post-prandial circulating glucose, insulin, and PYY concentrations, and ad libitum food intake on the 5th day following low flux and high flux phase conditions, respectively, completed in random order with a three-day washout period in between (see Figure 1).

Figure 1: Experimental Timeline | #Order of Low Flux and High Flux were randomly assigned (Foright. 2014).

During the low flux condition subjects remained sedentary for four consecutive days. All food was provided so that energy intakes were adjusted to maintain energy balance.

• resting metabolic rate (RMR) measurements on day 1-4 of the low flux phase
• caloric intake was adjusted according to RMR everyday
• subjects were fed standardized meals with a macro composition of 50/35/15 (carbohydrate/fat/protein) and an energy intake that was 1.3x the RMR
• subjects had to refrain from physical activity (>3,000 steps per day)
• at the end of day 5 the subjects completed a hunger/satiety questionnaire used to assess general feelings of hunger/satiety over the prior four days of the low flux condition

During the high flux condition subjects exercised on four consecutive days (approximately 500 net exercise kcal expenditure at 60% V02 max) and were fed additional food necessary to maintain energy balance.

• resting metabolic rate (RMR) measurements on day 1-4 of the low flux phase
• caloric intake was adjusted according to RMR everyday
• subjects were fed standardized meals with a macro composition of 50/35/15 (carbohydrate/fat/protein) and an energy intake that was 1.7x the RMR
• subjects were given pedometers and had to achieve at least 7,500 steps per day
• subjects exercised at 60% of their VO2max to burn 500kcal
• at the end of day 5 the subjects completed a hunger/satiety questionnaire used to assess general feelings of hunger/satiety over the prior four days of the low flux condition

Overall, a testing week consisted of two baseline days and 5 high/low energy flux days. In that, three identical experimental days were used to examine possible differences in perceptions of hunger and satiety, blood glucose, insulin, and PYY in response to breakfast preload, and ad libitum intake from a meal buffet.

Note: The caloric deficit that was designed to produce a 7% weight loss over the course of the 12-16 week long weight loss phase was identical in the undulating high and low energy flux phases of the study. The results are thus not a consequence of the increase in energy intake during the high flux phase (in fact the opposite was the case in some subjects, anway). The extra calories were after all burned again during the four exercise days.

"Now what is particularly interesting about the study is that the researchers did not content themselves with measuring the acute effects of high vs. low energy fluxes. They also investigated what happened after the 12-16 week weight loss phase.

To minimize the acute effects attributable to the dynamic phase of weight loss on metabolic rate and on hunger and circulating appetitive hormone concentrations, subjects were maintained at the seven percent lower body weight for a three-week period prior to the start of the low and high flux conditions. During these three weeks subjects reported to the KANC every three days to monitor weight and minimize weight fluctuations. Subjects were instructed to consume a slightly increased kcalorie intake compared to the weight loss phase to maintain weight" (Foright. 2014).

Put simply, the scientists wanted to know, whether the effects of high vs. low energy flux dieting would influence a dieters ability to lose weight and maintain the newly achieved weight.

Figure 2: Weight loss and energy flux where exactly as the scientists had planned (Foright. 2014)

As you can see, the average weight loss was almost identical to the targeted 7% (de facto "only" 6.9%). Similarly,

[...a]s designed, the energy intake for high flux (x±SD: 3,191±587 kcal/d) was significantly greater (p < 0.001) than for low flux (x±SD: 2,449±406 kcal/d) (Figure 2, right). In accord with the study design, there was no difference in macronutrient composition between the two conditions (data not shown)" (Foright. 2014).

Now all that would be pointless if both groups lost weight similarly effortlessly. In reality, though, On the subjects were significantly more hungry and felt less satiated at the end of each of the days during low flux.

Figure 3: As you see, the mean difference was already huge. It was more than huge in in
the subject who saw the greatest benefit (Foright. 2014).

On the other hand, they were significantly more full at the end of each of the days during high flux (p=0.015). There was a strong trend for the subjects to exhibit greater hunger throughout the day during low compared to high flux (p=0.09).

RMR increases sign. in trained but not untrained subjects in a high energy flux state - no training, no difference between the two groups - the energy balance was identical in both conditions (Bullough. 1995)

No, this is not an outlier study: In 1995 Bullough et al. were already able to show that the resting metabolic rate on diet + exercise regimen that established an identical energy balance was greater in trained than in untrained subjects only when trained subjects were in HF. As Bullough et al. point out "[t]hese data indicate that RMR is influenced by exercise, energy intake, and their interaction and suggest that higher RMR in trained vs untrained individuals results from acute effects of HF rather than from a chronic adaptation to exercise training." (Bullough. 1995) Bell et al. on the other hand found that "[m]aintenance of high energy flux via regular exercise may be an effective strategy for maintaining energy expenditure and preventing age-associated obesity" (Bell. 2013).

And Goran et al. (1994) found that "RMR can be elevated during a state of energy balance when energy flux is increased," and that the "magnitude of adaptive change in RMR is similar in response to increased EI [energy intake] and/or PA [physical activity]." 

Figure 4: The subject who saw the greatest satiety benefit in the high flux phase was also the one that consumed the most energy on the low flux condition - even more than on the high flux condition (Foright. 2014)

Interestingly, the subject who saw the largest benefit (see Figure 3) was also the guy or gal who consumed the most energy in the low flux condition (orange line in Figure 4).

So what about the health markers?

The  fasting insulin decreased following weight loss and was significantly lower on the LF (8.3±1.1 µU/ml) and HF (6.4±0.8 µU/ml) experimental days compared to the pre-weight loss baseline (11.8±0.6 µU/ml). In other words, while both groups saw significant increases in insulin sensitivity due to dieting, the effects were (unsurprisingly) significantly more pronounced during the high energy flux (=exercise phase).

In contrast to what the significant differences in hunger ratings would suggest, there were no general differences in fasting PYY (the satiety hormone) concentrations among pre-weight loss, low and high flux conditions respectively.

Figure 5: Insulin and PYY levels of the subjects in the high and low flux phases over the course of the day (2014).

If you look at the data in Figure 5, it's obvious that the PYY levels were in fact lower in the high flux condition - from 180-360 minutes in the high flux condition compared to the baseline (pre-weight loss) and low flux, to be precise.

Figure 6: Average resting metabolic rate at baseline and across 5 days of low and high flux (Foright. 2014)

So what? Beneficial, not beneficial, or not sure? In spite of the absence of significant differences in PYY, the post-diet response of the subjects clearly indicates that the energy deficit was easier to tolerate in the high flux phases.

The slightly, but significantly higher resting metabolic rate during the high flux phases further underlines that there is a benefit of eating more and training more and the absence of corresponding evidence from any of the hormonal markers measured may simply be related to a "bad" choice of markers. If the researchers had determined the level of the hunger hormone ghrelin, instes, it may well have been that we would have had a physiological explanation for the "hunger difference".

The way it is, we still have the decreased subjective hunger, increased subjective satiety and increased RMR which speak in favor of the high flux state dieting. What we do not know, though, is whether the effects will be the same in athletic (vs. sedentary) subjects [based on my personal experience we will!] and whether they can be maintained for say 4 weeks instead of four days | Comment on Facebook!

References:

• Bell, Christopher, et al. "High energy flux mediates the tonically augmented β-adrenergic support of resting metabolic rate in habitually exercising older adults." The Journal of Clinical Endocrinology & Metabolism 89.7 (2004): 3573-3578.
• Bullough, Richard C., et al. "Interaction of acute changes in exercise energy expenditure and energy intake on resting metabolic rate." The American journal of clinical nutrition 61.3 (1995): 473-481.
• Foright, Rebecca. A high energy flux state attenuates the weight loss-induced energy gap by acutely decreasing hunger and increasing satiety and resting metabolic rate. Diss. Colorado State University, 2014.
• Goran, Miachel I., et al. "Effects of increased energy intake and/or physical activity on energy expenditure in young healthy men." Journal of Applied Physiology 77.1 (1994): 366-372.
• Rarick, Kevin R., et al. "Energy flux, more so than energy balance, protein intake, or fitness level, influences insulin-like growth factor-I system responses during 7 days of increased physical activity." Journal of Applied Physiology 103.5 (2007): 1613-1621.

Thyroid Issues? Low Energy Intake Triggers Low T3 / High rT3 Syndrome in Exercising Women >19kcal/kg LBM Avail. Energy Required. Low Carbing Worsens the Impact of ED

It's not your thyroid, but your behavior that's to blame for your low T3 levels, the fatigue and being "unable to lose weight". If you exercised less and ate more, you could fix it without medical intervention or thyroid madness using Lugol's or other junk ;-)

It's something I am facing on a daily basis - on Facebook, in Emails and private messages: Women with self-induced thyroid issue who wonder that their body does everything to conserve lean and fat mass. Women who are working out on a daily basis, dieting like crazy and (in their words) "still not losing weight".

It does not take a thyroid expert to identify the reason for their problems: They are training too much and eating too little. Just like the 27 women in seminal experiment that was conducted at the Ohio University in the early 1990s. A study I am going to elaborate on in today's SuppVersity article, although I personally believe it shouldn't take experimental evidence to convince people (yes, this is true for men, as well) to stop run themselves into the ground.

Low T3 syndrome is also a part of the (Female) Athletes Triad.

Female Athletes' Body Comp Suf- fers From Dieting

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Female Athlete's Triad - Recovery Part 3/3

Said study was conducted by Anne B. Loucks and Edward M. Heath who worked at the Derpartment of Biological Sciences and the College of Osteopathic Medicine at the Ohio University back in 1994. The purpose of their study was to characterize the functional relationship between energy availability and thyroid metabolism to gain insight into the extent of he dietary reform that might be necessary. The scientists expected to find a proportional relationship that would prove the necessity of dietary compensation for exercise energy expenditure to prevent reductions in T3 levels, scientists call "low T3 syndrome".

To this ends, Loucks & Heath recruited 28 healthy, non-obese, nonsmoking women (18-29 years old) with no recent history of dieting or weight loss were recruited from the university and surrounding community. All received a detailed verbal and written description of the study and signed an informed consent document. The participants had to keep a prospective diet records for seven consecutive days a measure that was necessary to determine their baseline energy intake and
Subjects were assigned to four groups in a monotonic experimental design of energy availability treatments.

Figure 1: Overview of the experimental design (Loucks. 1994)

"The experimental manipulation of dietary energy intake, exercise energy expenditure, and, thereby, energy availability (defined as dietary energy intake minus energy expenditure during exercise) is shown in Fig. 1. All four experimental groups expended ~30 kcal kg LBM of energy in daily exercise at 70% of aerobic capacity for four consecutive days beginning on day 2, 3,4, or 5 of the menstrual cycle. All exercise was performed under continuous supervision on treadmill and cycle ergometers in a sequence of 30-min bouts interrupted by lo-min rest periods."  (Loucks. 1994)

During the first exercise bout, heart rate at 70% aerobic capacity was determined by monitoring oxygen uptake. Thereafter, heart rate was monitored continuously by means of a Uniq HeartWatch model 8799 (Computer Instruments, Hemstead, NY) and maintained at the previously measured level by adjusting treadmill speed and slope or cycle work load.

I know you will be asking, but aside from simply eating more there is no way to cure low T3 symptom. In fact the worst thing you can do is to get a script for T4 from your doc, because this will only elevate the inactive thyroid hormone (=break) rT3.

If the heart rate began to drift monotonically, suggesting a thermoregulatory effect, then oxygen uptake was measured directly by gas analysis. Heart rate and Borg scores of per- ceived exertion were recorded at the fourth and fifth minutes of each exercise bout.

Figure 2: Energy intake and expenditure (kcal/lbm) during the study period in all four grous (Loucks. 1999)

As you can see in Figure 2 the amount of available energy ranged from ~10kcal/kg lean body mass (LBM) in the group who had been assigned to the lowest amount of Ensure, a liquid food product that was the only food source the subjects received during the treatment period to ~40kcal/kg lean body mass in the group with the highest intakes.

Table 1: Thyroid hormone concentrations before treatment and changes in concentrations resulting from 4 days of controlled energy availability | Tq, thyroxine; fT4, free T,; T3, triiodothyronine; rT3, reverse T3; ff3, free T3 (Loucks. 1999)

As you can see in Table 1 the thyroid hormone concentration in the two lower groups (10kcal and 19kcal/kg lbm) dropped significantly. With a 10% decrease in free T3 only the changes in the 10.8kcal /kg lbm group were physiologically significant.

Bottom line: In a previous experiment (12), the scientists had been able to show that energy availability, rather than dietary energy intake or exercise energy expenditure separately, is the behavioral factor affecting thyroid regulation in exercising women. It is thus not exactly surprising that 4 days on an energy deficient diet in the study at hand were enough to induce a low T3 syndrome in the female participants of the study at hand.

Figure 3: Mean T3 thyroid hormone levels after 20 days of total fasting, 800kcal diet without carbohydrates and 800kcal diet consisting almost exclusively of carbs (Spaulding. 1976)

In this context it's important to point out that the effect occured only, when the dietary inake fell below 50% of the dietary requirement and that the changes in thyroid hormone levels are restricted to T3 and won't show up on tests that evaluate TSH and T4, only.

In studies of the effects of dietary restriction on thyroid metabolism in sedentary obese patients, T3 levels declined only when dietary energy intake fell below a particular threshold and the carbohydrate con- tent of the diet influenced the location of this threshold. T3 levels fell when energy intake was reduced to 800 kcal/day if carbohydrate content was <200kcal/day. Previous studies also highlight that a reduction of carbohydrate intake, will reduce the amount of free T3 by increasing the conversion of T4 to the inactive thyroid metabolite rT3.

Irrespective of the fact that a high(er) carbohydrate diet can help women maintain normal thyroid function on a diet, studies indicate that there is an energy threshold below the amounts of carbs in the diet become irrelevant and the T3 levels crash as a simple consequence of a lack of energy in the diet (Spaulding. 1976) | Comment on Facebook!

References:

• Loucks, Anne B., and Edward M. Heath. "Induction of low-T~ 3 syndrome in exercising women occurs at a threshold of energy availability." American Journal of Physiology 266 (1994): R817-R817. 
• Spaulding, Stephen W., et al. "Effect of caloric restriction and dietary composition on serum T3 and reverse T3 in man." The Journal of Clinical Endocrinology & Metabolism 42.1 (1976): 197-200.

More Than -2kg Body Fat in 4 Days? Manic Exercise and a 4-Day x 5,000kcal Energy Deficit on Whey or Sucrose Based Starvation Diet Yield Astonishingly Long-Lasting Fat Loss

Actually, even cherry tomatoes were not allowed in the first 4 days ;-)

Wow! If that's what you thought, when you read the figure in the headline you know what I thought, when I spotted the latest paper from the University of Las Palmas de Gran Canaria in the "ahead of print" section of the Scandinavian Journal of Medicine & Science in Sports (Calbet. 2014).

I mean, the title of the study, "a time-efficient reduction of fat mass in 4 days with exercise and caloric restriction", sounds pretty harmless. Too harmless for what happened to the 15 subjects the researchers recruited for an experiment that was almost as extreme as its astonishing results.

Wake up, work out, starve and sleep

I would say the above summarizes pretty well what I was referring to, when I said "something happened to the subjects" in the first 4 days of the study, the 15 not exactly lean study participants (mean BMI ~30kg/m²; body fat 31%) started their days with 45min of an arm cranking exercise (at 15% maximal intensity; see Figure 1).

Figure 1: Schematic overview of the different phases of the diet + exercise intervention (Calbet. 2014)

When they were done, they spend most of the remaining waking hours day walking - 8 h of walking at 4.5 km/h (35 km/day) 4 days in a row and on a diet delivering meager 3.2 kcal/kg body weight from a shake that contained either pure whey protein or pure sucrose.

This can't really be the whey to go? Right?

What sounds like some mad survival program did, as you can see in Figure 1, produce quite impressive weight loss effects. Unfortunately, this is "weight", as in fat and muscle and that at an almost 1:1 ratio - certainly not the type of "weight loss" any of you should strive for.

Figure 2: Lean mass (left) and fat mass (right) development during the four phases of the intervention (Calbet. 2014)

Now, the fat rebound in the sucrose group would initially suggest that your gut feeling was right. Eventually, it's yet unlikely that this was more than a mere coincidence and the shocking loss in lean mass that occurred during the 4-day of manic dieting + walking, normalized withing days, when when the subjects returned to their regular energy intakes (+ obligatory 10,000 steps a day).

The latter obviously suggests that most of the "muscle loss" was actually water + glycogen and thus easy to restore (see Figure 3, right, as well).

Suggested Read: "Cell Swelling Keeps Muscles "Pumped" For More Than 52h - Could It Even Help You Build Muscle?" | read more

Lean mass can be tissue, water and glycogen: Early "muscle loss" is mostly water + glycogen (esp. on low carb diets; Kreitzman. 1992). In view of older studies on the muscle-building mechanisms of creatine (Persky. 2001) and the latest research on the involvement of muscular (hyper-)hydration in skeletal muscle hypertrophy Ribero et al. (2014), the loss of water and glycogen - as benign and as far as the glycogen goes, even metabolically beneficial (leaves room to store glucose ➲ improves insulin sensitiviy) as it may be - could hamper your gains.

What I cannot explain - at least not without telling you that my answer is of hypothetical nature and would thus require experimental confirmation - are the impressive long(er)-term weight loss effects.
Usually you would expect the subjects to jojo back up, right away - in the worst case to body fat levels that are higher than those nasty 31%, where they were initially coming from. If you take a look at Figure 3, it's yet plain to see that the opposite was the case.

Figure 3: Progressive changes in body fat and lean mass (in kg) over the course of the study period (Calbet. 2014)

In spite of the fact that the subjects returned to their regular energy intakes, they lost an additional body fat - at quite an impressive rate, by the way. Now, an as previously mentioned hypothetical explanation for these observations is the use of body fat as a substrate and energy source to refill the previously mentioned glycogen stores in muscle and liver.

Even if we take into consideration that the release (lipolysis) and oxidation of fats and the storage of glucose from dietary carbohydrates (it's not impossible (Kaleta. 2012), but unlikely that the stored body fat is used as an energy source for glyconeogenesis) in form of glycogen are energetically costly, the 2,000kcal would equal no more than max. 300g of stored body fat, which is more than the additional 450g even the whey protein group dropped during the 4-day aftermath.

That's quite astonishing: Would you have expected that this "4-days of madness" diet would generate a total fat loss of -3.8kg (2.8kg of those from the potentially life-threatening trunk fat) and thus produce an outcome of which the researchers rightly say that it "is better than several interventions combining low-calorie diets and exercise lasting from 12 weeks to 1 year (Garrow. 1995; Shaw. 2009)" and bet the largest randomized control trial for the response to 8-month resistance training, aerobic training, or combined aerobic and resistance training (Willis et al., 2012)? Certainly not, right?

Figure 4: Weight loss (not fat loss!) maintenance in Calbet et al. and the average US dieter according to a meta-analysis by Anderson et al. (2001)

Well, considering the fat that the mean fat loss here is greater than that achieved by the latest pharmacological intervention, i.e. the administration of glucagon-like peptide-1 (GLP-1) agonists for 20 weeks (which gave a weighted mean loss of 2.9 kg in 21 trials involving 6411 participants; Vilsboll. 2012), I am actually happy that there was a one year follow up to show that a short-term intervention can never replace permanent life-style changes... although, when you look at the whey protein group, who regained a meager 1.09kg in Phase V and thus significantly less than the 50-80% the average subject on a medically supervised weight loss diets (Anderson. 2001; see Figure 4), I do have to admit this is not just surprising.

This is damn impressive, even if the comparison is unfair, due to longer follow ups in the average study in Anderson's meta-analysis. Still, there is one thing I would like to see before I'd recommend this type of diet to anyone who doesn't have to lose another 2kg of fat before a physique show or photoshoot at the end of the week: A comparison of the health benefits of successful whey-based(!) crash dieting.

References:

• Anderson, James W., et al. "Long-term weight-loss maintenance: a meta-analysis of US studies." The American journal of clinical nutrition 74.5 (2001): 579-584.
• Calbet, J. A. L., et al. "A time-efficient reduction of fat mass in 4 days with exercise and caloric restriction." Scandinavian Journal of Medicine & Science in Sports. (2014). Accepted Manuscript. doi: 10.1111/sms.12194 
• Garrow, J. S., and C. D. Summerbell. "Meta-analysis: effect of exercise, with or without dieting, on the body composition of overweight subjects." European journal of clinical nutrition 49.1 (1995): 1-10.
• Kaleta, Christoph, Luís F. de Figueiredo, and Stefan Schuster. "Against the stream: relevance of gluconeogenesis from fatty acids for natives of the arctic regions." International journal of circumpolar health 71 (2012).
• Kreitzman, Stephen N., Ann Y. Coxon, and Kalman F. Szaz. "Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition." The American journal of clinical nutrition 56.1 (1992): 292S-293S.
• Persky, Adam M., and Gayle A. Brazeau. "Clinical pharmacology of the dietary supplement creatine monohydrate." Pharmacological Reviews 53.2 (2001): 161-176.
• Ribeiro, Alex S., et al. "Resistance training promotes increase in intracellular hydration in men and women." European journal of sport science ahead-of-print (2014): 1-8. 
• Shaw, K., et al. "Exercise for overweight or obesity." Cochrane Database Syst Rev 4 (2006).
• Vilsbøll, Tina, et al. "Effects of glucagon-like peptide-1 receptor agonists on weight loss: systematic review and meta-analyses of randomised controlled trials." BMJ: British Medical Journal 344 (2012).
• Willis, Leslie H., et al. "Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults." Journal of Applied Physiology 113.12 (2012): 1831-1837.