New study on calories in vs. calories out, protein intake and body composition

First time study on weight gain including macro intake and body composition analysis. The results may not be surprising, but still interesting to see the numbers. 

Cliffs: 
- 3 diet groups: low-protein (5% of cals), normal-protein (15% of cals), high-protein (25% of cals)
- the 3 groups were put on overfeeding diet for 8 weeks
- low-protein gained 3.6kg, normal-protein gained 6.1kg, high-protein gained 6.5kg

BUT: all groups gained 3.5kg FAT, the low-protein group however lost 0.7kg LBM and the normal-protein group and high-protein group both gained LBM (resp. 3.2kg and 4.0kg). Non of the groups did any exercise. As a bonus, resting calorie expenditure increased in the normal-protein and high-protein group. 

So yes, calories in VS. calories out determines fat gain (when overfeeding) but higher protein intake adds LBM.
 

Intervention
After consuming a weight-stabilizing diet for 13 to 25 days, participants were randomized to diets containing 5% of energy from protein (low protein), 15% (normal protein), or 25% (high protein), which they were overfed during the last 8 weeks of their 10- to 12-week stay in the inpatient metabolic unit. Compared with energy intake during the weight stabilization period, the protein diets provided approximately 40% more energy intake, which corresponds to 954 kcal/d (95% CI, 884-1022 kcal/d).

Main Outcome Measures
Body composition was measured by dual-energy x-ray absorptiometry biweekly, resting energy expenditure was measured weekly by ventilated hood, and total energy expenditure by doubly labeled water prior to the overeating and weight stabilization periods and at weeks 7 to 8.

Results
Overeating produced significantly less weight gain in the low protein diet group (3.16 kg; 95% CI, 1.88-4.44 kg) compared with the normal protein diet group (6.05 kg; 95% CI, 4.84-7.26 kg) or the high protein diet group (6.51 kg; 95% CI, 5.23-7.79 kg) (P = .002). Body fat increased similarly in all 3 protein diet groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure, total energy expenditure, and body protein did not increase during overfeeding with the low protein diet. In contrast, resting energy expenditure (normal protein diet: 160 kcal/d [95% CI, 102-218 kcal/d]; high protein diet: 227 kcal/d [95% CI, 165-289 kcal/d]) and body protein (lean body mass) (normal protein diet: 2.87 kg [95% CI, 2.11-3.62 kg]; high protein diet: 3.18 kg [95% CI, 2.37-3.98 kg]) increased significantly with the normal and high protein diets.

Conclusions
Among persons living in a controlled setting, calories alone account for the increase in fat; protein affected energy expenditure and storage of lean body mass, but not body fat storage.

 
Source: http://jama.ama-assn.org/content/307/1/47.short
 
A video for those you you who don't like reading 

Maybe I'm being thick, but if the low protein group were the only ones whose resting metabolic rate didn't increase, how come they gained less weight? You would have thought that the increased RMR for the higher protein groups would have limited the weight gain to some extent, yet they gained more weight.
 
Great study by the way, 3 months in a metabolic ward, doubly labelled water, rigorously controlled,if only all dietary studies could be like this one!

No you're not being thick, it's a good question.
 
Note that they all gained the same amount of fat at the same calorie surplus.  But, that being said the low protein ALSO lost lean body mass where as the normal/high protein gained lbm.
 
Off to the gym (LOL, yes I actually do lift and just don't read studies all day  )

Good stuff. Would like to see the full paper but all looks sound indeed.

Yes, the muscle gain is definitely a positive but it still means that the higher-protein groups gained more weight (regardless of what the weight was) on, theoretically, a slightly lower calorie surplus due to the increased RMR.

Yeah I know what you mean.
It would be interesting to see the same study done on resistance trainees.

Interesting read.
 
I think it would, as Liddy said, be interesting to see how the results faired for the same test with people eating the same way (low, medium, high protein, etc) but instead of doing no exercise, lifted weights.
 
Nick

Will have to see if I can DL this paper now.

Nice study - a full text would be great if anyone can grab?
 
Regarding the RMR I would have thought that could be down to when the candidates had their rates measured - protein affects RMR for longer than carbs/fats, with a peak around the 3hr mark - see here http://en.wikipedia.org/w...dial_thermogenesis.png - so measuring at the 'wrong' time would affect how things look.
 
Given that fundamentally the same amount of fat was laid down, they weren't caning through an awful lot more calories. Plus, the ~3kg of LBM added will have been added over time, not just lumped on on day 1 - so there might have been an initial period where they had higher fat gain (protein being insulinogenic) that was then tapered off to start on fat loss, dunno - does seem a bit counter-intuitive.
 
As it stands, 6lbs of LBM in 8 weeks, whilst doing nothing = WTF! I'd be pretty happy to add 6lbs in a year, training hard, lol!