Interaction of Fat Cell Size, Protein Intake & Co. W/ Fat Gain + Insulin Res. in Overfed Men + Women in Metabolic Ward

Interaction of Fat Cell Size, Protein Intake & Co. W/ Fat Gain + Insulin Res. in Overfed Men + Women in Metabolic Ward

adipocyte size fat cell fat cell sizes gain fat gylcemia health high protein homa-ir insulin insulin resistance lose fat overfeeding subcutaneous fat visceral fat visceral obesity

That's rather the low protein variety of overfeeding... but wait, was the high protein diet even "high" in protein? Well high enough to affect liver fat, for sure.

You will probably remember José Antonio's high protein overfeeding study series (learn more) from the articles here and on the SuppVersity Facebook page. The results were quite impressive, but the number of controlled covariates were small and the dietary control was limited to food logs.

In a more recent study, George A. Bray and colleagues from the Pennington Biomedical Research Center of the Louisiana State University System, the George Mason University, and the FL Hospital & Sanford-Burnham Prebys Discovery Research Institute (Bray. 2016) determined the effect of overfeeding diets with 5%, 15% or 25% energy from protein on glycemia + body fat distribution in healthy men and women with add. covariates and in a metabolic ward.

Yes, the high protein intake clogged the liver during overfeeding

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In total, 15 men and 5 women were overfed by 40% (extra calories above maintenance) for 56 days with diets containing

• 5% (LP) of the total energy as protein, 
• 15% (NP) of the total energy as protein, or 
• 25% (HP) of the total energy as protein

Insulin sensitivity was measured using a two-step insulin clamp at baseline and at 8 weeks. Body composition and fat distribution were measured by DXA and multi-slice CT scan ... so far not so different, but the subjects were contained in a metabolic ward, cheating on the diet was thus as impossible, as taking supplements or working out like maniacs.

Figure 1: Diagram that illustrates the 8-weekstudy design; N = 10 male, 5 female subjects (Bray. 2016).

In conjunction with the scientists' analysis of the subjects abdominal subcutaneous fat cell size, which was determined on osmium fixed fat cells, these are two strengths of a study, of which it is yet quite obvious that it also had its disadvantages:

• 

  Review the effects of different macronutrients in overfeeding studies | more

  the protein content of the diet is simply hilarious - that's not just because eating 5% protein, only is nothing but idiotic, but also because 25% of protein is far away from what can be considered "high protein" these days;
• the lack of exercise limits the significance of the results - at least for the majority of SuppVersity readers overeating in phases in which you don't exercise is probably nothing they would even remotely consider.

The scientists observations that neither the subjects' insulin sensitivity and free fatty acids during low and high levels of insulin infusion did not differ after 8 weeks of overfeeding.

Figure 2: Effect of 8 weeks of overfeeding on abdominal fat distribution, ectopic lipid; rel. changes (Bray. 2016).

What did differ, however, were the changes in body fat distribution according to DXA and how the latter depended on the protein content on fat cell size before the overfeeding period. More specifically, ...

• the fat free mass (FFM) and intrahepatic lipid increased more on the high protein, whereas 
• % BF and fasting free fatty acids (FFA) increased more on the low protein diet, while

In addition, the scientists observed that a high initial fat cell size predicted increased visceral fat gains and the FFA suppression during the high-dose insulin clamp.

Figure 3: Relation of Baseline Fat Cell Size to Change in Visceral Adipose Tissue Mass with Eight Weeks of
Overfeeding in heathy volunteers (VAT 0.040 +/- 0.70(FCS); P < .0063 | Bray. 2016)

The subjects' insulin levels at baseline, on the other hand, predicted the increase in subcutaneous but not visceral fat accumulation (see Figure 3) - most intriguingly with low fasting insulin
at baseline correlated predicting higher changes in % fat (for insulin the scientists observed a correlation with r = –0.43; P < .034), but not with other variables. It is thus not surprising that the most insulin sensitive subjects also gained the most subcutaneous fat... or, as the scientists put it: "HOMA IR predicted the increase in DSAT (r = 0.50; P <.016), but not other variables" (Bray. 2016).

Those are important insights of which the authors rightly point out that they clearly indicate that "an induction of insulin resistance with overfeeding is related to fat cell size and requires more than an expansion of adipose tissue stores" (Bray. 2016).

A surprising, but not debatable result of the study at hand is that the high protein diet increased liver fat (HUs;  measured with DXA, too).  The low protein diet, on the other hand, helped to decrease the subjects' liver fat significantly - remember: we are talking about a diet with 40% extra energy on top of the regular diet (Bray. 2016).

Bottom line: Yes, you've read all that in individual articles (albeit often about rodent studies) on SuppVersity before: (1) the more protein, the greater the lean mass gains; (2) the less protein, the greater the ratio of fat to lean mass gains; (3) the fuller your fat cells, the more likely you will gain metabolically unhealthy visceral fat; and (4) the more insulin sensitive you still are, the more metabolically healthier subcutaneous fat you will gain.

What is news, or at least has not been observed in Antonio's study in active individuals (also because they didn't look) is the surprisingly ill effect of high amounts of protein on liver fat (see Figure, right): while the low protein diet reduced the subjects' liver fat sign, the high protein diet triggered a small, but undesirable accumulation of liver fat during overfeeding in normal-weight subjects - not good, but not yet critical and hopefully something you'd not see w/ concomitant exercise or smaller calorie excess | Comment!

References:

• Bray, George A., et al. "Effect of three levels of dietary protein on metabolic phenotype of healthy individuals with 8 weeks of overfeeding." The Journal of Clinical Endocrinology & Metabolism (2016): jc-2016.

52% Reduced Fat Gain Over 4 Weeks of Overfeeding Twenty Young Men W/ 1000 kCal/Day on a High Fat (55%) Diet Due to Double Dose of a Commercial Multistrain Probiotic

52% Reduced Fat Gain Over 4 Weeks of Overfeeding Twenty Young Men W/ 1000 kCal/Day on a High Fat (55%) Diet Due to Double Dose of a Commercial Multistrain Probiotic

high fat high fat diet lose fat overfeeding probiotics

Probiotics act on in the digestive tract, but their effects are still systemic.

You've read about the anti-weight gain effects of probiotic supplements in rodents before at the SuppVersity and in the SuppVersity Facebook News. Nice, yes, but will this also work in human beings? If we put faith into the predictive quality of a recent from Virginia Tech, it should.

Before we delve deeper into the study design, results and evaluation in the bottom line, I'd yet like you to know that (a) we don't know if the effects will persist for more than 4-weeks, if they will become stronger or weaker and that (b) the study was funded by VSL Pharmaceuticals (Osterberg. 2015) - both additional reasons not to confuse a single study like this with "proof" that probiotics block fat gain.

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The objective of Osterberg's latest study was to "determine the effects of the probiotic, VSL#3, on body and fat mass, insulin sensitivity, and skeletal muscle substrate oxidation following 4 weeks of a high-fat diet" - in humans, and even better in 20 non-obese men (18-30 years) who participated in the study.

Learn everything about overfeeding! How do the effects of high vs. low fat, high vs. low protein and high vs. extra-high energy intake differ, what's the effect on thyroid and other important hormones and more

"All testing took place at the Human Integrative Physiology Laboratory between the hours of 5:00 and 11:00 am. Participants fasted for 12 h, did not consume caffeine or alcohol, performed no vigorous physical activity for the prior 48 h, and were free from acute illness for the prior 2 weeks.

[...]Following a 2-week eucaloric control diet, participants underwent dual X-ray absorptiometry to determine body composition, an intravenous glucose tolerance test to determine insulin sensitivity, and a skeletal muscle biopsy for measurement of in vitro substrate oxidation" (Osterberg. 2015). 

Subsequently, participants were randomized to receive either VSL#3 (2x450 billion bacteria), a dietary probiotic supplement that contains a motley mix of bacteria, i.e. Streptococcus thermophilus DSM24731, Lactobacillus acidophilus DSM24735, Lactobacillus delbrueckii ssp. bulgaricus DSM24734, Lactobacillus paracasei DSM24733, Lactobacillus plantarum DSM24730, Bifidobacterium longum DSM24736, Bifidobacterium infantis DSM24737, and Bifidobacterium breve DSM24732, or placebo daily during 4 weeks.

Figure 1: Composition (in g/day) and energy consumption (kcal/day) of the lead in and high fat diet (Osterberg. 2015).

Both, i.e. the probiotic supplement VSL#3 as well as the placebo supplement, were consumed alongside a high fat milk shake which also served to bring up the total energy intake (+1,000kcal/day) and relative contribution of fat from 8% to 55% compared to the standardized diet that was used in the 2-week lead in. Practically speaking, we are thus looking at a standardized high fat overfeeding study with or without probiotic intervention.

Figure 2: Changes in body composition in response to 4-week high fat overfeeding with or without probiotic supplementation (VSL#3, a 900 billion multi-strain probiotic) in 20 normal-weight young men (Osterberg. 2015).

A study that yielded interesting results, but results that are of questionably practical relevance. Yes, there was a statistical group effect for the changes in total body mass (0 kg vs. 0.8kg) and the total body fat mass (+1.1% vs. +2.4%).

Since there were neither significant differences in body fat% due to the lower lean mass gains in the probiotic group and considering the fact that there were no additional health effects in form improvements in insulin sensitivity or fat oxidation. Since neither of them was affected by the overfeeding, anyways, the significance of the lack of change is questionable.

Bottom line: In spite of the statistically significant weight and fat gain differences, the interpretation of the study at hand is not 100% straight forward. This may be due to the fact that within only 4 weeks other changes (esp. health relevant parameters) did not occur in either group.

While this study shows no immediate health benefits, there's evidence that gluten sensitive individuals may benefit from supplementing /w certain strains.

Furthermore, it must be said that the reduced lean mass gains in the probiotic strain and the subsequent lack of changes in body fat percentages, suggest that the amelioration of the subjects' weight gain is mediated by a mere reduction in energy-availability (this assumes that the intakes in both groups were identical to begin with). If this is the case, the supplement still has its merits: According to the questionable approximation that says that it takes 7,000kcal extra to gain 1kg of body fat, the probiotic supplementation would have compensated for 1.3 kg x 7000 kcal/kg = 9100kcal over 4 weeks and 325 kcal/ day (note this is not a scientifically accurate calculation).

Still, much more research is going to be necessary - not only to elucidate the exact mechanism, but also to find out if the effect might depend on the type of diet: A high fat diet, for example, has been shown to have significant, potentially detrimental effects on the human gut microbiome, which may be meditated by the bile acid resistance of several strains of bacteria, i.e. more fat = exuberant bile production = death to many good bacteria (David. 2014) |  Comment on Facebook!

References:

• David, Lawrence A., et al. "Diet rapidly and reproducibly alters the human gut microbiome." Nature 505.7484 (2014): 559-563.
• Osterberg, et al. "Probiotic Supplementation Attenuates Increases in Body Mass and Fat Mass During High-Fat Diet in Healthy Young Adults." Obesity (2015): Ahead of print.