Effects of low‐fat and low‐GI diets on health

Abstract

PurposeExcess weight and poor quality diets are known to be major and manageable causes of cardiovascular diseases (CVD) but the optimal diet for the prevention and reduction of CVD risk is not known. The purpose of this paper is to compare the effects of low‐fat and low‐GI diets on weight loss, liver function and CVD risk factors.Design/methodology/approachIn total, 18 overweight/obese females were randomly assigned to eight weeks of either isocalorie (1,200 kcal day) low‐fat (<20 per cent energy intake as fat) or low‐GI (≤40 per cent energy intake as carbohydrate) diet. Participants kept a one week food and drink intake diary prior to starting the prescribed diet (week 0) and during weeks 4 and 8 of the diet. BMI, blood pressure, serum lipids, AST and ALT concentrations were measured at specific time intervals.FindingsThe low‐fat group reported more adequate micronutrient intake than the low‐GI group. Mean weight, BMI and systolic blood pressure reduced significantly in each group but there was no significant difference between groups. There was no significant change in mean LDL, HDL and total cholesterol concentration within and between groups. Mean triglyceride reduced significantly (33 per cent) in the low‐GI group but there was no significant change in the low‐fat group. The low‐GI diet significantly reduced ALT concentration by 16 per cent after four weeks but there was no significant change for the low‐fat group.Originality/valueThe paper shows that a low‐GI diet may be more effective at reducing CVD risk and improving liver function than a low‐fat diet. This extends data on a previous studies that compared low‐fat and low‐GI diets.