Less Fat, More Muscle: The Effects of Adding a High Protein Intake on Top of a Hypercaloric Diet in Humans Are Slim, But the Body Composition Trend (FFM ￪, Fat ￬) is Significant

Cottage cheese is a good source of extra protein - 11-12g/100g

Protein is a wonderful substance. You all know that, so much, in fact that most of you expect way too much from this one macronutrient and forget about the usefulness and need of the others. Don't worry I am not going to lecture you, if you want to go on a rabbit starvation diet, as the early American explorers were forced to eat (almost exclusively eating lean meats will result in nausea, then diarrhea, and then death; Speth. 1983), it's obviously your life and hapiness you're throwing away.

But let's not get off track, here. The twenty-nine healthy, young, lean Caucasian men and women in the study at hand were after all not "rabbit starved".
Rather than that, the subjects of one of the latest studies from the Wageningen University in the Netherlands underwent a 6-week dietary intervention that began with a 2-wk run-in period on a weight-maintaining CD (27.8 en% fat, 16.9 en% protein, 55.3 en% carbohydrates) that should help the subjects to familiarize with the diet.

Thereafter, participants were randomly assigned to either the HD group (n= 19) or the CD reference group (n= 10). The subjects in the HD group were overfed with 2 MJ/d for the following 4 wk of intervention; within the HD group, a randomized crossover design consisting of 2 periods of 2 wk was applied:

• 2-wk High Protein (HP) intervention - protein content 25.7 en%  220g/day
• 2-wk Normal Protein (LP) intervention -  protein content 15.4 en%,123g/day

The starting diet was chosen randomly. The crossover occured after two weeks. Parallel to the HD group, the reference group continued on the weight-maintaining CD for another 4 wk. The health parameters of interest, that were measured were

• the intrahepatic lipid content (IHL) as marker of NAFLD,
• the fasting blood glucose, insulin, and triglyceride concentration as diabesity markers,
• body composition, adipose tissue gene expression, and resting energy expenditure (REE)

All measurements were performed after an overnight fast at the research facilities of Wageningen University.
The body weight was measured two times per week on a calibrated scale. During the run-in period, energy intake was adjusted in case of weight change. The contribution of SFAs was kept at;10 en%, as dietary guidelines recommend, and accounted for 9.5 en% in the CD and 11.5 en% in the HD in both the HP and NP conditions. Dietary compliance was assessed by completion of a diary by the participants, return of emptied food packages, and measurement of 24-h urine urea concentration by kinetic UV assay.

Figure 1: Rel. changes (% of baseline) in triglycerides, intra-hepatic lipids (IHL) and body weight (left); lean mass vs. fat mass comparison after high (HP) vs. normal protein (NP) +478kcal "bulk" (Rietmann. 2014)

If you take a look at the consequences of the 478kcal/day extra, you will probably come back to the notion of rabbit starvation and the idea that 27% of the total energy intake in form of protein is far from being "too high in protein"... well, you're right - compared to the absurd amounts of protein I see in the diets of some fitness fanatics who are still wondering, why they are constantly fatigued, that's rather mediocre. If we do the match on the 3439.38kcal/day baseline, we do yet get a protein intake of 3.2g/kg - which is PLENTY!
Reference:

• Rietmann, et al. Increasing Protein Intake Modulates Lipid Metabolism in Healthy Young Men and Women Consuming a High-Fat Hypercaloric Diet. J. Nutr. August 1, 2014 jn.114.19107.
• Speth JD, Spielmann KA. Energy source, protein metabolism, and hunter-gatherer subsistence strategies. J Anthropol Archaeol 1983; 2:1–31