Effect of protein overfeeding on energy expenditure measured in a metabolic chamber.
BACKGROUND
Energy expenditure (EE) increases with overfeeding, but it is unclear how rapidly this is related to changes in body composition, increased body weight, or diet.


OBJECTIVE
The objective was to quantify the effects of excess energy from fat or protein on energy expenditure of men and women living in a metabolic chamber.


METHODS
We conducted a randomized controlled trial in 25 participants who ate ∼40% excess energy for 56 d from 5%, 15%, or 25% protein diets. Twenty-four-hour EE (24EE) and sleeping EE (SleepEE) were measured on days 1, 14, and 56 of overfeeding and on day 57 while consuming the baseline diet (usually day 57). Metabolic and molecular markers of muscle metabolism were measured in skeletal muscle biopsy specimens.


RESULTS
In the low-protein diet group whose excess energy was fat, the 24EE and SleepEE did not increase during the first day of overfeeding. When extra energy contained protein, both 24EE and SleepEE increased in relation to protein intake (r = 0.50, P = 0.02). The 24EE over 8 wk in all 3 groups was correlated with protein intake (r = 0.60, P = 0.004) but not energy intake (r = 0.16; P = 0.70). SleepEE was unchanged by overfeeding in the low-protein diet group, and baseline surface area predicted increased 24EE in this group. Protein and fat oxidation were reciprocally related during overfeeding. Observed 24EE was higher than predicted on days 1 (P ≤ 0.05), 14 (P = 0.0001), and 56 (P = 0.0007). There was no relation between change in fat mass and change in EE.


CONCLUSIONS
Excess energy, as fat, does not acutely increase 24EE, which rises slowly as body weight increases. Excess energy as protein acutely stimulates 24EE and SleepEE. The strongest relation with change in 24EE was the change in energy expenditure in tissue other than muscle or fat-free mass.
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
George A
GA
Bray
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Leanne M
LM
Redman
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Lilian
L
de Jonge
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Jeffrey
J
Covington
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Jennifer
J
Rood
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Courtney
C
Brock
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Susan
S
Mancuso
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Corby K
CK
Martin
From the Pennington Biomedical Research Center, Baton Rouge, LA (GAB, LMR, JC, JR, CB, SM, and CKM); George Mason University, Arlington, VA (LdJ); and Translational Research Institute for Metabolism and Diabetes Florida Hospital and Sanford Burnham Institute, Orlando, FL (SRS).
Steven R
SR
Smith
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D018752:Diet, Fat-Restricted / Q000009:adverse effects*; D059305:Diet, High-Fat / Q000009:adverse effects; D018753:Diet, Protein-Restricted / Q000009:adverse effects; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D006963:Hyperphagia / Q000378:metabolism*; D008297:Male; D052097:Quadriceps Muscle / Q000378:metabolism*; D057185:Sedentary Behavior; D016037:Single-Blind Method; D022722:Thermogenesis; D015854:Up-Regulation; D015430:Weight Gain; D055815:Young Adult
D015415:Biomarkers; D004044:Dietary Proteins
adaptive thermogenesis; hormones; low-protein diet; molecular markers; sleeping energy expenditure