Effects of increasing increments of fat- and sugar-rich snacks in the diet on energy and macronutrient intake in lean and overweight men.

Two studies have examined the effect on energy intake and macronutrient selection of increasing increments of mandatory high-fat or high-sugar snacks into the diet in men. The present study used a within-subject, repeated-measures design. In each experiment, six lean and six overweight, unrestrained men were each studied over three 7 d treatment periods, during which they were given mandatory snacks of the same energy density (550 kJ/100 g) comprising the following (in terms of percentage energy as fat-carbohydrate-protein): high-fat, 80:10:10; high-sugar, 10:80:10, of which 65 % was sugar, and 15 % starch. Subjects were given 0, 1.5 or 3.0 MJ/d snacks, in a randomised counterbalanced design, to be consumed mid-morning and mid-afternoon. Throughout each day, subjects had access ad libitum to fifteen high-protein, fifteen high-fat and fifteen high-carbohydrate foods, rotated on a 3 d menu. Mandatory high-fat snacks significantly elevated energy intake and fat intake, whereas high-sugar snacks elevated energy intake and carbohydrate intake (all P<0.02). Mandatory increases in sugar intake did not displace fat from the diet or vice versa. It was concluded that the ingestion of up to 3 MJ/d high-fat and high-sugar foods promoted weak compensation (18 % and 30 %, respectively) and therefore elevated daily energy intake by approximately 2.0-2.5 MJ.