-
[show abstract]
[hide abstract]
ABSTRACT: The role of diet composition in response to overeating and energy dissipation in humans is unclear.
To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition.
A single-blind, randomized controlled trial of 25 US healthy, weight-stable male and female volunteers, aged 18 to 35 years with a body mass index between 19 and 30. The first participant was admitted to the inpatient metabolic unit in June 2005 and the last in October 2007.
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).
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.
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.
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.
clinicaltrials.gov Identifier: NCT00565149.
JAMA The Journal of the American Medical Association 01/2012; 307(1):47-55. · 30.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Fast food is consumed in large quantities each day. Whether there are differences in the acute metabolic response to these meals as compared to 'healthy' meals with similar composition is unknown.
Three-way crossover.
Six overweight men were given a standard breakfast at 8:00 a.m. on each of 3 occasions, followed by 1 of 3 lunches at noon. The 3 lunches included: (1) a fast-food meal consisting of a burger, French fries and root beer sweetened with high fructose corn syrup; (2) an organic beef meal prepared with organic foods and a root beer containing sucrose, and (3) a turkey meal consisting of a turkey sandwich and granola made with organic foods and an organic orange juice. Glucose, insulin, free fatty acids, ghrelin, leptin, triglycerides, LDL-cholesterol and HDL-cholesterol were measured at 30-min intervals over 6 h. Salivary cortisol was measured after lunch.
Total fat, protein and energy content were similar in the 3 meals, but the fatty acid content differed. The fast-food meal had more myristic (C14:0), palmitic (C16:0), stearic (C18:0) and trans fatty acids (C18:1) than the other 2 meals. The pattern of nutrient and hormonal response was similar for a given subject to each of the 3 meals. The only statistically significant acute difference observed was a decrease in the AUC of LDL cholesterol after the organic beef meal relative to that for the other two meals. Other metabolic responses were not different.
LDL-cholesterol decreased more with the organic beef meal which had lesser amounts of saturated and trans fatty acids than in the fast-food beef meal.
Annals of Nutrition and Metabolism 02/2007; 51(2):163-71. · 2.26 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study was designed to document the mechanism through which globin digest, a dietary herbal supplement, might cause weight loss by exploring possible fat malabsorption, calorie malabsorption, energy expenditure, and fat oxidation. Six healthy subjects were placed on an outpatient diet for 14 days and given a meal containing 40.9 g of fat on days 5 and 11, and stools were collected for 72 hours after each meal for analysis of fecal fat content. Four grams of globin digest was given with one meal and placebo with the other. In another separate study, six subjects were placed on a 100-g fat, weight-maintaining diet for 14 days. All food was prepared by the Pennington Center (Baton Rouge, LA) metabolic kitchen. Globin digest (2 g) or placebo was given with each of three meals per day, and stool was collected for calorie determinations during the last 72 hours of each week. Subjects received globin digest during one of the 2 weeks and placebo during the other. Resting metabolic rate and respiratory quotient were measured on the last day of each 1-week period. There was no increase in 72-hour fecal fat or fecal calories by bomb calorimetry during either of the studies. There was no difference in the respiratory quotient. Globin digest did result in an increase in resting metabolic rate. However, this increase was not statistically significant. Globin digest, if effective, does not cause weight loss or fat loss through fat malabsorption or a relative increase in fat oxidation. Future studies are needed to document the efficacy of globin digest for weight loss in humans before further mechanistic investigation is attempted.
Journal of Medicinal Food 02/2006; 9(4):579-81. · 1.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The purpose of the present study was to determine the effects of supraphysiologic doses of triiodothyronine (T(3)) on skeletal metabolism, calcium balance, and the calciotropic hormones. Seven healthy, lean men were studied in an inpatient metabolic unit over a 63-day period. All volunteers received oral T(3) at doses of 50-75 microg/d. There was a prompt and sustained increase in calciuria and an overall net negative calcium balance. The pattern of changes in serum osteocalcin, urinary deoxypyridinoline (DPD)/creatinine ratio, and serum bone-specific alkaline phosphatase indicated an early increase in bone resorption followed by a late, incomplete compensatory increase in bone formation. Cumulative net calcium loss was 18.5 +/- 5.4 g over the 63-day treatment period, averaging 218.5 +/- 41.4 mg/d. This represents 0.22% +/- 0.075% of the total skeletal calcium content. The cumulative net calcium loss over the 63-day treatment period was highly correlated with the change in DPD (r = -0.95, p = 0.001). Prompt increases in corrected serum calcium values resulted in serum intact parathyroid hormone (iPTH) levels decreasing by 30.4% (p = 0.08). Bone mineral density showed no change. We conclude that T(3) accelerates bone turnover and that bone formation does not increase acutely to prevent bone loss.
Thyroid 05/2003; 13(4):357-64. · 4.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Context
The role of diet composition in response to overeating and energy dissipation in humans is unclear.Objective
To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition.Design, Setting, and Participants
A single-blind, randomized controlled trial of 25 US healthy, weight-stable male and female volunteers, aged 18 to 35 years with a body mass index between 19 and 30. The first participant was admitted to the inpatient metabolic unit in June 2005 and the last in October 2007.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.Trial Registration
clinicaltrials.gov Identifier: NCT00565149
Figures in this Article
Obesity has become a major public health concern with more than 60% of adults in the United States categorized as overweight and more than 30% as obese.1- 2 People who become obese have been in a positive energy balance for an extended period. Swinburn et al3 have argued that this reflects an increase in food intake, but Church et al4 have presented data showing that reduced occupational activity might account for the positive energy balance. Although a majority of people in the United States are overweight or obese, there is a significant number of people with normal weights who do not become overweight or obese. As obesity develops, a number of metabolic changes occur, which may not completely reverse when weight is lost.5 These differences may reflect differences in the way individuals handle the food they eat each day both during weight gain and weight loss.
The concept that when people overeat the amount of weight gain is highly individual has intrigued medical science for a century.6- 9 In a critical review of macronutrient composition and response to overfeeding, Stock10 cites 12 studies in human beings to support the view that when people overeat a diet that contains either high or low protein, they are less “metabolically efficient” than diets of average protein intake.10- 19 This concept is appealing from an evolutionary perspective because the ability to waste “excess” calories when eating an unbalanced diet would ensure an adequate supply of nutrients while avoiding risks to survival as a result of excess weight gain.20- 21 In Stock's analysis,10 the greatest metabolic efficiency of weight gain during overfeeding was found when protein intake was 10% to 15% of the energy consumed. Conversely, the metabolic inefficiency or “wasting” of calories during overfeeding appeared when diets contained low or high amounts of energy from protein.22 Overeating a diet low or high in dietary protein may maintain body weight through metabolic inefficiency because of the energy cost involved in sparing lean body mass with a low protein diet but expanding lean body mass with a high protein diet.20
This study was designed to determine whether the level of dietary protein differentially affected body composition, weight gain, or energy expenditure under tightly controlled conditions in a randomized controlled trial.
JAMA The Journal of the American Medical Association 307(1):47-55. · 30.03 Impact Factor
