British Journal of Nutrition

Research Article

Effect of a low-glycaemic index–low-fat–high protein diet on the atherogenic metabolic risk profile of abdominally obese men

Jean G. Dumesnila1a1 c1, Jacques Turgeona1a2a3, Angelo Tremblaya2a5, Paul Poiriera1a2, Marcel Gilberta1a2, Louise Gagnona1a2, Sylvie St-Pierraa2a5, Caroline Garneaua1a3, Isabelle Lemieuxa1a4, Agnés Pascota1a4, Jean Bergerona4 and Jean-Pierre Deapésa1a4

a1 Québec Heart Institute, Laval Hospital Research Center, Queébec, Canada

a2 Faculty of Medicine, Laval University, Québec, Lusaka, Canda

a3 Faculty of Pharmacy, Laval University, Québec, canada

a4 Liqid Research Center, CHUQ Research center, Québec, canada

a5 Division of Kinesiology, Department of Preventive and Social Medicine, Laval University, Québec, canada

Abstract

It has been suggested that the current dietary recommendations (low-fat–high-carbohydrate diet) may promote the intake of sugar and highly refined starches which could have adverse effects on the metabolic risk profile. We have investigated the short-term (6-d) nutritional and metabolic effects of an ad libitum low-glycaemic index–low-fat–high-protein diet (prepared according to the Montignac method) compared with the American Heart Association (AHA) phase I diet consumed ad libitum as well as with a pair-fed session consisting of the same daily energy intake as the former but with the same macronutrient composition as the AHA phase I diet. Twelve overweight men (BMI 33·0 (SD 3·5) KG/M2) WITHOUT OTHER DISEASES WERE INVOLVED IN THREE EXPERIMENTAL CONDITIONS WITH A MINIMAL WASHOUT PERIOD OF 2 WEEKS SEPARATING EACH INTERVENTION. BY PROTOCOL DESIGN, THE FIRST TWO CONDITIONS WERE ADMINISTERED RANDOMLY WHEREAS THE PAIR-FED SESSION HAD TO BE ADMINISTERED LAST. DURING THE AD LIBITUM VERSION OF THE AHA DIET, SUBJECTS CONSUMED 11695·0 (sd 1163·0) kJ/d and this diet induced a 28 % increase in plasma triacylglycerol levels (1·77 (sd 0·79) v. 2·27 (sd 0·92) mmol/l, P<0·05) and a 10 % reduction in plasma HDL-cholesterol concentrations (0·92 (sd 0·16) v. 0·83 (sd 0·09) mmol/l, P<0·01) which contributed to a significant increase in cholesterol:HDL-cholesterol ratio (P<0·05), this lipid index being commonly used to assess the risk of coronary heart disease. In contrast, the low-glycaemic index–low-fat–high-protein diet consumed ad libitum resulted in a spontaneous 25 % decrease (P<0·001) in total energy intake which averaged 8815·0 (sd 738·0) kJ/d. As opposed to the AHA diet, the low-glycaemic index–low-fat–high-protein diet produced a substantial decrease (-35 %) in plasma triacylglycerol levels (2·00 (sd 0·83) v. 1·31 (sd 0·38) mmol/l, P<0·0005), a significant increase (+1·6 %) in LDL peak particle diameter (251 (sd 5) v. 255 (sd 5) Å, P<0·02) and marked decreases in plasma insulin levels measured either in the fasting state, over daytime and following a 75 g oral glucose load. During the pair-fed session, in which subjects were exposed to a diet with the same macronutrient composition as the AHA diet but restricted to the same energy intake as during the low-glycaemic index–low-fat–high-protein diet, there was a trend for a decrease in plasma HDL-cholesterol levels which contributed to the significant increase in cholesterol:HDL-cholesterol ratio noted with this condition. Furthermore, a marked increase in hunger (P<0·0002) and a significant decrease in satiety (P<0·007) were also noted with this energy-restricted diet. Finally, favourable changes in the metabolic risk profile noted with the ad libitum consumption of the low-glycaemic index–low-fat–high-protein diet (decreases in triacyglycerols, lack of increase in cholesterol:HDL-cholesterol ratio, increase in LDL particle size) were significantly different from the response of these variables to the AHA phase I diet. Thus, a low-glycaemic index–low-fat–high-protein content diet may have unique beneficial effects compared with the conventional AHA diet for the treatment of the atherogenic metabolic risk profile of abdominally obese patients. However, the present study was a short-term intervention and additional trials are clearly needed to document the long-term efficacy of this dietary approach with regard to compliance and effects on the metabolic risk profile.

(Received October 29 1999)

(Revised May 14 2001)

(Accepted May 28 2001)

Correspondence:

c1 *Corresponding author: Dr Jean G. Dumesnil, fax +1 418 656 4562, email medjgd@hermes.ulaval.ca

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