The Effect of Casein Protein Prior to Sleep on Fat Metabolism in Obese Men.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 27472361 · doi:10.3390/nu8080452
What was done
Twelve obese men (mean age 27.0 ± 2.2 years) participated in a randomized crossover study to evaluate the acute effects of pre-sleep protein ingestion. Within 30 minutes of going to sleep, subjects ingested either casein protein (CAS, 120 kcal) or a non-nutritive placebo (PLA). Microdialysis was used to measure interstitial glycerol in subcutaneous abdominal adipose tissue (SCAAT) during sleep and the next morning to assess lipolysis. Substrate utilization, resting energy expenditure (REE), blood markers (lipolysis markers, growth hormone, insulin, glucose, ghrelin), and appetite questionnaires were also assessed.
What was found
There were no significant differences between CAS and PLA for SCAAT glycerol overnight (CAS: 177.4 ± 26.7 μmol/L; PLA: 183.8 ± 20.2 μmol/L) or the next morning (CAS: 171.6 ± 19.1 μmol/L; PLA: 161.5 ± 18.6 μmol/L). Additionally, no differences were observed between CAS and PLA for substrate utilization, REE, or any blood markers. Desire to eat was significantly higher than baseline after CAS (baseline: 39 ± 6 mm vs. CAS: 62 ± 8 mm, p = 0.03), but did not differ significantly from PLA (55 ± 5 mm).
Why it matters
These findings suggest that a modest dose of casein protein consumed before sleep can be ingested without impairing overnight lipolysis or morning resting metabolism in young obese men.
Limits
The study was limited by a very small sample size (n = 12) restricted to young, hyperinsulinemic obese men. It assessed only acute, single-night ingestion of a low-calorie protein serving (120 kcal), so long-term outcomes, higher caloric doses, and generalizability to other populations were not evaluated.
Cited by
- supports Research by Mike Ormsbee demonstrates that consuming 40 grams of protein 30 minutes before bed does not impair fat oxidation or increase body fat gain.