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

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/m 2 ) 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 lowglycaemic 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 (235 %) 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:HDLcholesterol 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. T...

Long-term effects of popular dietary approaches on weight loss and features of insulin resistance

“…Zone) 5 diets, which have been shown in many studies of free-living individuals to be associated with impressive weight loss and improved cardiovascular risk indicators over a relatively short period of time (up to 6 months). [6][7][8][9][10][11][12][13][14][15][16] Very few data are available relating to longterm (12 months or greater) comparisons of such alternative dietary regimens 6,[17][18][19][20] and only one study has been published that compares HP, HF and the more widely recommended HC-high-fibre diet over a prolonged period. 21 We have previously reported a 6-month comparison of such diets in overweight insulin-resistant women.…”

Effectiveness of energy-restricted diets with different protein:carbohydrate ratios: the relationship to insulin sensitivity

“…Replacement of some dietary carbohydrates by protein (25 % v. 12 % energy intake from protein) in an ad libitum fat-reduced diet have previously been shown to induce a greater weight loss (8?9 v. 5?1 kg) due to a lower energy intake (5000 kJ/d (1195 kcal/d) v. 6201 kJ/d (1482 kcal/ d)) (22) . Another study also confirmed these findings but, when compared with an isoenergetic high-carbohydrate diet, high-protein diets did not imply a significant difference in body weight loss (23) . It has been reported that 1 kg of weight loss translates into an energy deficit of 30?5 MJ (7300 kcal) in women (24) .…”

Potential benefits of satiety to the consumer: scientific considerations

“…However, evidence suggests that satiety-enhancing low-energy diets, particularly those high in fibre and complex carbohydrate, can suppress hunger and the desire to eat, and increase feelings of wellbeing (95,129,130,163,164) .…”

“…Acute food deprivation increases the reinforcing value of food (127,128) , the subjective appeal of high-energy density foods and the activation of brain reward systems in response to pictures of these (43) . Sustained, hypoenergetic diets generally produce increased reports of hunger (94,110,114,129,130) and changes in hunger in response to dieting can predict successful/unsuccessful weight maintenance (131) . Experimental studies of semistarvation demonstrate that restriction of energy intake can produce profound effects including preoccupation with food, unrelenting thoughts of food and eating, distraction and limited concentration (for example, Franklin et al (132) ).…”