ENERGY-INTAKE AND BODY-WEIGHT EFFECTS OF 6 MONTHS REDUCED OR FULL-FATDIETS, AS A FUNCTION OF DIETARY RESTRAINT

OBJECTIVE: Assessment of the effect of six months consumption of reduc ed fat or full fat products on energy intake and body weight, as a fun ction of dietary restraint. DESIGN: A small realistic supermarket in t he University departments provided full fat commercial products and th eir reduced fat alternatives. Volunteers visited the supermarket once a week. Half of them were required to take the reduced fat products, t he other half the full fat products. They bought additional products i n normal shops. SUBJECTS: Two matched groups (age, genders, body mass index (BMI)), one dietary restrained and one dietary unrestrained, wer e derived from the total group of 220 healthy men and women. This resu lted in four groups differing in dietary restraint and in belonging to the full fat or reduced fat group. MEASUREMENTS: Energy intake, macro nutrient composition of food intake, energy density and weight of food ingested were measured before the run-in period and at 2-4 weeks, thr ee and six months after the start of the study, by controlled food int ake diaries. RESULTS: Percentage energy from fat, and energy density c hanged significantly, according to the reduced or full fat diet, in al l subjects. Energy intake and body weight remained constant in the die tary unrestrained on a reduced fat diet and in the dietary restrained on a full fat diet. Energy intake increased significantly, with a tren d of body weight increase in the dietary unrestrained on a full fat di et. Body weight decreased significantly, with a trend of decreased ene rgy intake, in the dietary restrained on a reduced fat diet. CONCLUSIO N: A reduced fat diet, in combination with unrestrained eating behavio ur which resulted in energy intake compensation, contributed to weight maintenance. Weight reduction was the consequence of a reduced fat di et in combination with restrained, non-compensatory eating behaviour. A full fat diet combined with unrestrained eating behaviour led to inc reased energy intake. Restrained eating behaviour with a full fat diet prevented an increase in energy intake and body weight. Thus dietary restraint compensated for an increase in energy density, whereas dieta ry unrestraint compensated for a decrease in energy density.