Chicken, Rice, Veggies & Oil and How Their Effects on Your Insulin & Glucose Levels Are 50% Off Those You'd Expect Based on the Calculated Glycemic Index of This Meal

The power of GI calculations is limited and even with meals as simple as the one in the picture, the calculated glycemic index can be ~50% off!

As a SuppVersity reader you've repeatedly read about macronutrient interactions, such as the insulin boosting effects of whey protein or dietary fat, studies that investigate the effects of the individual ingredients of a complete meal on the glycemic response healthy men and women, however, are scarce. Against that background the results of a recent study from the Clinical Nutrition Research Centre at the Singapore Institute for Clinical Sciences are of particular interest. After all, the Lijun Sun et al. (2014) determined the effect of co-ingesting a high-protein food (breast chicken), a fat (ground nut oil), a leafy vegetable or all three on the glycaemic and insulinaemic responses of white rice in healthy adults and did thus produce results that could be practically relevant for all of us - more relevant than inaccurately calculated GIs.

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Before we get to the study results, though, let's briefly recap what the researchers actually did: Sun et al. recruited twelve healthy participants (six female and six male) by means of advertisements, flyers and personal communications.

"Before inclusion into the study, potential participants were briefed on all aspects of the experiment and were given the opportunity to ask questions. Following the securing of consent, a health assessment was performed which included anthropometric measurements and a health questionnaire (giving details of food allergies/intolerance, metabolic diseases, special dietary needs and smoking habits). Those who fulfilled all the inclusion criteria [body mass index 18.5–24.99 kg/m2; blood pressure (BP)—systolic BP between 110 and 120 mmHg and diastolic BP between 75 and 85 mmHg; age 21–50 years; fasting blood glucose, 4–6 mmol/L; not on prescription medication, non-smoking; no genetic or metabolic diseases) were enrolled into the study." (Sun. 2014)

In addition, the amount of regular physical activity was quantified and subjects who were partaking in competitive sports and endurance events were excluded. Eventually, the scientists ended up with a group of normal-weight men and women at the age of 21–34 years.

Table 1: Composition of the test meals, ACHO = available carbohydrates.
Nutritional data were obtained from the manufacturers (Sun. 2014).

The subjects visited the laboratory 5 times (plus a baseline testing with a glucose solution). On each of these testing sessions, which were separated by at least one week, the subjects arrived at the laboratory between 7:30 and 8:30 after an overnight fast and received one of the five test meals from Table 1, which contained 194 g white of plain white rice,  254 g of white rice with fat, 294 g of plain white rice with chicken breast, 314g of white rice with vegetable and 474g of white rice with fat, chicken and vegetable, respectively.

Ground nut oil? I guess most of you will know the oil that was used in the study at hand as "peanut oil" and it is - as you will probably know, as well - not exactly high in "holy" omega-3 fatty acids. Rather than that, peanut oil contains oleic acid (46.8% as olein), linoleic acid (33.4% as linolein), and palmitic acid (10.0% as palmitin), as well as small amounts of stearic acid, arachidic acid, arachidonic acid, behenic acid, lignoceric acid, but not a singly milligram of omega-3s.
The test or reference food was then given to consume within 15 min. Further blood samples for glucose and insulin analysis were taken for the subsequent 180 min (every 15 min in the first hour and every 30 min for the subsequent hours) - a procedure that yielded the following results.

Figure 1: Glucose levels expressed relative to the ingestion of 250g of glucose (Sun. 2014)

The values in Figure 1 are expressed relative to the glucose response to 250g of pure glucose, of which a brief glimpse at the data tells you that they produce higher peak and incremental area under the curve (iAUC, a measure for the glycemia over the whole testing period) levels than any of the meals. Statistical significant differences were yet observed only for rice with chicken breast, rice with vegetable, and rice with fat, chicken and vegetable - yet not for the plain rice and the rice + fat meal (the latter was to be expected based on the discussion in my previously referenced article "True or False? Adding Fat to A Carby Meal Lowers Insulin Response" | read more).

Significant differences for the insulin response were observed for the white rice + chicken meal, where the insulin response was significantly higher compared to the white rice only (+22%), as well as the rice with + vegetable meal, where the insulin response was significantly lower compared to the white rice only condition (-16%).

The combination of foods determines the GI of the meal

Based on the classic equation that's usually used to determine the glycemic index of a meal (Hätönen. 2011), Sun et al. calculated the predicted glycemic of the five test meals and compared it to the actual glycemic index (GI) that was calculated based on the measured glucose and insulin response of the subjects.

Figure 2: Predicted and measured glycemic index as well as measured insulinemic index of the meals (Sun. 2014)

As you can see in Figure 2, the comparison yields an unsurprising result. As it's usually the case, when simple equations are used to predict physiological effects, the real GI values were significantly different from the calculated ones and  - significantly lower, that is. Accordingly, the meal with the least impact on postprandial glycemia and a comparatively low insulinemic effect is the one containing rice, fat, chicken and veggies - in other words, the complete meal. 

Suggested Read: "Get Your Protein, Veggies & Fruits and Get Them Regularly: High(er) Meal Frequency (6 à Day) + High(er) Protein Diet Support Weight & Fat Loss on a Diet." | read more

Bottom line: While the importance of the glycemic index (GI) has long been totally overrated, there is accumulating evidence that high postprandial glucose levels are a significant contributor to increases in cardiovascular disease risk even in healthy individuals (Einarson. 2011; Mah. 2011). Against that background the results of this recent trial support my previous recommendation to consume balanced meals containing protein, fat and carbohydrates, instead of no-fat or no-carb meals.

In contrast to what the "paleo hypothesis" and the notion that our ancestors would not have collected some berries or boiled some rice to have it alongside the chicken they just caught would say, the contemporary scientific evidence indicates that we are well equipped to handle complex meals, as long as they don't contain exorbitant amounts of fat and carbohydrates.

One thing we should not forget, though, is that the 50% discrepancy between the calculated and real glycemic index of the "complex" test meal (four ingredients is not exactly "complex", actually) suggests that one of the reasons that many of the previous studies failed to detect a meaningful association between the (obviously calculated) GI of an individuals diet and his / her cardiovascular or diabetes risk may be that the data the scientists used was similarly inaccurate as the predicted glycemic indices of the test meal in the study at hand | Comment on Facebook!

References:

• Hätönen, Katja A., et al. "Protein and fat modify the glycaemic and insulinaemic responses to a mashed potato-based meal." British Journal of Nutrition 106.02 (2011): 248-253.
• Mah, Eunice, et al. "Postprandial hyperglycemia impairs vascular endothelial function in healthy men by inducing lipid peroxidation and increasing asymmetric dimethylarginine: arginine." The Journal of nutrition 141.11 (2011): 1961-1968. 
• Sun, Lijuan, et al. "Effect of chicken, fat and vegetable on glycaemia and insulinaemia to a white rice-based meal in healthy adults." European journal of nutrition (2014): 1-8.
• Wolever, T. M. S. "Is glycaemic index (GI) a valid measure of carbohydrate quality&quest." European journal of clinical nutrition 67.5 (2013): 522-531.

Fishing for Muscle: Cod Protein Promotes Muscle Repair After Injury More than Casein or Peanut Protein

Image 1: There are obviously more nutritionally valuable parts to cod than just its liver.

On Wednesday, you have learned that diet-deoptimization with rice instead of casein protein is a possible way to gain less weight. Today, we are going to tackle what appears to be a way more promising alternative to the dairy-based top-dogs among the protein supplements: Cod protein! Within the health and fitness community, the cold(er) water fish is hitherto, above all, known for its vitamin-laden liver and the oil humans have been producing from it and consuming for centuries, now. That the arginine-, glycine- and taurine-rich protein of its tasty white flesh could soon replace - or at least complement - dairy proteins (casein, whey) as the physical culturists' go-to protein for muscle building and regeneration will yet probably be news to most of you, right?

COD - Canned or dried? Probably doesn't matter as long as you eat it.

In a recently published paper on yet another rodent protein feeding trial (Dort. 2012), Junio Dort and his colleagues from the Laval University and the Research Center of CHUQ, CHUL in Quebec, Canada, report that the artificially injured tibialis muscle of rodents that were kept on cod-protein based diets for 21-days healed significantly faster than the skeletal muscle of the peanut or casein protein control groups.

Figure 1: Amino acid profile of casein, peanut and cod protein source on which the otherwise identical rodent diets were based (based on Dort. 2012)

For the smart SuppVersity student you are, it should not take more than just a brief glance at the amino acid profiles of the three protein sources to identify cod protein and casein as superior and peanut (as it was to be expected) inferior protein source. With -24% and -30% less branched-chain (BCAA) and total essential amino acids (EAA), peanut protein would certainly not be the first choice of any non-vegan physical culturist, let alone bodybuilder, who is interested in opti- and not deoptimizing his his/her diet (on an unrelated not: Don't you Americans never refer to the ladies, first? I always read "his/her" - that would not exactly be gentleman-like here, in Germany!).

118 neutrophils and still counting: Cod protein (not oil, in this case) tames the inflammation

In order to assess how peanut, casein and cod-based diets would modulate the rodents' response to muscular injury the animals were treated with bupivacaine, a substance that is myotoxic ("kills" muscle cells, but - and this is a specialty of bupicacaine - not satellite cells) at higher doses (here 100µL). The drug was injected into one of the animals' tibialis muscles, while the contra-lateral side was sham-injected (saline injection) to serve as a control. At days 3, 14, and 24 post-injury, both the injured and sham-injected tibialis muscles were "collected" (8 animals per dietary group) and the neutrophil count, and macrophage infiltration - both measures of ongoing inflammation and thusly incomplete healing subsequent to prior muscle damage - were assessed.

Figure 2: Neutrophil count and EDI+ macrophage count in bupivacaine injected tibialis muscle 3 and 14 days and 14 and 24 days after the injection; data expressed relative to sham control (data calculated based on Dort. 2012)

As the data in figure 2 goes to show, the cod protein group showed a markedly faster reduction in neutrophil and EDI+ macrophage count than the casein group, which - in a separate experiment - had already been found to sustain the healing process better than the nutritionally inferior peanut proteins, which also exhibited a -19% lower feeding efficacy (meaning that similar to the rice protein in Wednesday's newspost, it lead reduced weight gain; again, not necessarily desirable, specifically in injured rats) and, "in results previously published, [...] lower skeletal muscle mass than those fed casein [even] before injury" (Dort. 2012).

The anti-inflammatory effects of cod protein reach beyond skeletal muscle

Though muscle is, as my friend Carl Lanore likes to say, "metabolic currency" and it's protection and repair should be on everyone's, man and women top list of health priorities, the benefits of cod protein extend beyond skeletal muscle. A brief review of the literature revealed among others ...

• increases in HDL, decreasse in VLDL with cod over casein and soy (Jacques. 1995)
• restoration of GLUT-4 activity in skeletal muscle of HFD obese rodents (Trembley. 2003)
• lower hepatic triglyceride production vs. beef or casein (Demonti. 2003)
• lowest insulin / glucose ratio (vs. soy or casein), when given as part of complex test meal (Post-Skagegard. 2006)
• improvements in insulin sensitivity and reductions in C-reactive protein vs. diet containing beef, pork, veil, eggs and dairy in insulin resistant men and women (Ouellet. 2007; Ouellet. 2008)

Just as the improved healing of the muscoskeletal injury in the rodent study at hand, most of the aforementioned effects are probably attributable to the modulatory the homemade cod protein (the scientists simply used frozen cod fillets to prepare their protein powder) exerts on the immune system. In this context, it is particularly important to mention that

[...] an impairment of insulin-stimulated glucose uptake and a reduction of protein synthesis, combined with an increase of muscle protein degradation, are the main adverse metabolic changes induced by injuries in skeletal muscle.

In previous studies, the researchers were also able to show that the profound impairment of the AKT /PKB pathway, which is one of the key mechanisms behind the nutrient induced increase of protein synthesis, is protected from the impairments of "high fat diets" (the researcher variety, which is more akin to the standard American than to "low carb" diet), if the latter contains cod, instead of soy- or casein-protein (Tremblay. 2003).

Arginine for repair, EAA for growth: It may be of interest that Dort et al. attribute the muscle building and muscle repairing effects of cod protein to different amino acid in the cod protein. While they believe that its high arginine content suffices as NO precursor to drive and accelerate the repair process, they hold the high essential amino acid (EAA) content responsible for its pro-anabolic effects which are comparable to those of casein (and probably even whey) proteins.

Image 2: Fish is not for you? Maybe you just don't know how to prepare it properly? It's not really difficult to grill a fillet, trust me - even I can do that.

It stands to reason, that both the restoration and / or maintenance of skeletal muscle mass and insulin sensitivity, as well as the general anti-inflammatory properties of cod protein (remember: the protein in the study was derived directly from frozen fillets and contained almost no fat!) come handy for everyone who wants to live a healthy and active live into the old age. In this regard the study result do not only underline the importance and multifaceted benefits of regular fish consumption (fatty or not) as part of a healthy diet, they also support my repeatedly proffered believe that the latter should not be defined by macronutrient ratios, let alone calories, but must be build around concrete meal and food suggestions, as well as general and flexible recommendations regarding the frequency and combinations in which these can be consumed.