December 8/Maastricht, Netherlands/Health & Medicine Week -- Data detailed in "Presence or Absence of Carbohydrates and the Proportion of Fat in a High-protein Diet Affect Appetite Suppression but Not Energy Expenditure in Normal-weight Human Subjects Fed in Energy Balance" have been presented. "Two types of relatively high-protein diets, with a normal or low proportion of carbohydrates, have been shown effective for weight loss. The objective was to assess the significance of the presence or absence of carbohydrates and the proportion of fat in high-protein diets for affecting appetite suppression, energy expenditure, and fat oxidation in normal-weight subjects in energy balance," scientists in Netherlands report.

"Subjects (aged 23 (sd 3) years and BMI 22·0 (sd 1·9) kg/m2) were stratified in two groups. Each was offered two diets in a randomised cross-over design: group 1 (n 22) -normal protein (NP; 10, 60 and 30 % energy (En%) from protein, carbohydrate and fat), high protein (HP; 30, 40 and 30 En%); group 2 (n 23) -normal protein (NP-g; 10, 60 and 30 En%), high protein, carbohydrate-free (HP-0C; 30, 0 and 70 En%) for 2 d; NP-g and HP-0C were preceded by glycogen-lowering exercise (day one). Appetite was measured throughout day two using visual analogue scales (VAS). Energy expenditure (EE) and substrate oxidation (respiratory quotient; RQ) were measured in a respiration chamber (08.00 hours on day two until 07.30 hours on day three). Fasting plasma ß-hydroxybutyrate (BHB) concentration was measured (day 3). NP-g and NP did not differ in hunger, EE, RQ and BHB. HP-0C and HP v. NP-g and NP, respectively, were lower in hunger (P < 0·05; P < 0·001) and RQ (P < 0·01; P < 0·001) and higher in EE (P < 0·05; P = 0·07) and BHB (P < 0·05; P < 0·001). Hunger and RQ were lower with HP-0C than HP (693 (sd 208) v. 905 (sd 209) mm VAS x 24 h, P < 0·01; 0·76 (sd 0·01) v. 0·81 (sd 0·02), P < 0·01); BHB was higher (1349 (sd 653) v. 332 (sd 102) mol/l; P < 0·001). ?Hunger, ?RQ, and ?BHB were larger between HP-0C-NP-g than between HP-NP ( - 346 (sd 84) v. - 107 (sd 52) mm VAS x 24 h, P < 0·01; - 0·09 (sd 0·00) v. - 0·05 (sd 0·00), P < 0·001; 1115 (sd 627) v. 104 (sd 42) mol/l, P < 0·001)," wrote M.A. Veldhorst and colleagues, Maastricht University.