Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum

Abstract
Abstract Background: Altering the macronutrient composition of dietary intake influences hunger and satiety. Many studies have compared high-protein and high-carbohydrate weight loss diets, but none compare high-protein diets with low and medium supply of carbohydrate in order to assess the potential impact of ketosis on motivation to eat and ad libitum intake. Objective: To assess hunger and appetite response to a high-protein-low-carbohydrate (HPLC, ketogenic) and high-protein-medium-carbohydrate (HPMC, non-ketogenic) diet, in obese men feeding ad libitum. Design: Seventeen obese (mean BMI 35.1 kg/m2), but otherwise healthy, men volunteered for a residential trial of 9 weeks duration. Each subject participated in two 4-week dietary intervention periods, each preceded and followed by a 3d maintenance phase. Subjects were allowed to eat ad libitum from excess food provided daily. Body weight was measured daily and motivation to eat was assessed hourly during waking hours, using a computerised visual analogue system. Results: With both HP diets, voluntary intakes were lower than on maintenance (p<0.001). Ad libitum energy intake was significantly lower on the HPLC diet, compared with the HPMC diet (p=0.02), with average intakes of 7.25 and 7.95MJ/d, respectively. Over the four weeks, hunger was lower on the HPLC diet (p=0.020). Weight loss was greater on the HPLC diet, compared with the HPMC diet, with average losses of 6.34 and 4.35 kg, respectively (p=0.006). Body fat loss was also greater on the HPLC diet (5.2 v 4.1 kg, p=0.083). Conclusions: High-protein-low-carbohydrate, ketogenic diets appear, in the short-term at least, to promote satiety in obese men, suggesting that the combination of high-protein and low-glucose supply does influence perceived appetite and motivation to eat.
Year
2008
Category
Refereed journal
Output Tags
SG 2006-2011 WP 4.2 Metabolic Health