|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.|
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.
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
|Figure 1: Diagram that illustrates the 8-weekstudy design; N = 10 male, 5 female subjects (Bray. 2016).|Review the effects of different macronutrients in overfeeding studies | more
- 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.
|Figure 2: Effect of 8 weeks of overfeeding on abdominal fat distribution, ectopic lipid; rel. changes (Bray. 2016).|
- 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
|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)
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).
- 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.