Energy intake and body weight effects of six months reduced or full fat diets, as a function of dietary restraint.

OBJECTIVE: Assessment of the effect of six months consumption of reduced fat or full fat products on energy intake and body weight, as a function of dietary restraint. DESIGN: A small realistic supermarket in the University departments provided full fat commercial products and their reduced fat alternatives. Volunteers visited the supermarket once a week. Half of them were required to take the reduced fat products, the other half the full fat products. They bought additional products in normal shops. SUBJECTS: Two matched groups (age, genders, body mass index (BMI)), one dietary restrained and one dietary unrestrained, were derived from the total group of 220 healthy men and women. This resulted in four groups differing in dietary restraint and in belonging to the full fat or reduced fat group. MEASUREMENTS: Energy intake, macronutrient composition of food intake, energy density and weight of food ingested were measured before the run-in period and at 2-4 weeks, three and six months after the start of the study, by controlled food intake diaries. RESULTS: Percentage energy from fat, and energy density changed significantly, according to the reduced or full fat diet, in all subjects. Energy intake and body weight remained constant in the dietary unrestrained on a reduced fat diet and in the dietary restrained on a full fat diet. Energy intake increased significantly, with a trend of body weight increase in the dietary unrestrained on a full fat diet. Body weight decreased significantly, with a trend of decreased energy intake, in the dietary restrained on a reduced fat diet. CONCLUSION: A reduced fat diet, in combination with unrestrained eating behaviour which resulted in energy intake compensation, contributed to weight maintenance. Weight reduction was the consequence of a reduced fat diet in combination with restrained, non-compensatory eating behaviour. A full fat diet combined with unrestrained eating behaviour led to increased 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 dietary unrestraint compensated for a decrease in energy density.

Effect of replacement of fat by nonabsorbable fat (sucrose polyester) in meals or snacks as a function of dietary restraint.

The effect of replacement of fat by nonabsorbable fat on energy intake and on feelings of hunger and satiety was assessed, in normal-weight dietary-restrained (n = 11), dietary-unrestrained (n = 13) and in postobese dietary-restrained women (n = 12), using 2 experimental designs. First, during breakfast and lunch on 2 sequential weekdays, 23 g of dietary fat was replaced by 23 g of a nonabsorbable fat. Second, dietary fat was replaced by a nonabsorbable fat in snacks consumed ad lib during a different week. Fat replacement in meals or in snacks did not result in changes in hunger and satiety ratings throughout the day. Replacement in meals yielded an energy intake reduction of 0.5 MJ/day (not significant) in dietary-unrestrained and in postobese dietary-restrained subjects; this reduction included 44% energy intake compensation. In normal-weight dietary-restrained subjects, energy intake reduction of 0.7 (p < 0.05) MJ/day was observed; this reduction included 22% energy intake compensation. Moreover, fat replacement in meals showed a shift in macronutrient composition from 35-40% energy from fat to 31-32% energy from fat. Replacement in snacks yielded an energy intake reduction of 0.4-0.5 MJ/day (not significant) in normal-weight dietary-restrained subjects and a reduction of 0.6-0.7 (p < 0.05) MJ/day in dietary-unrestrained and in postobese dietary-restrained subjects. In this situation, energy intake from snacks consisted of 48-78% energy from reduced-fat reduced-energy snacks, which implied a replacement of 10-15 g fat by 10-15 g SPE (sucrose polyester) and a shift in macronutrient composition from 35-40 percentage energy from fat to 33-36 percentage energy from fat. These results suggest short-term beneficial effects of fat replacement on energy and fat intake.

Diet-induced thermogenesis and satiety in humans after full-fat and reduced-fat meals.

Diet-induced thermogenesis was measured during and after a full-fat lunch, an identical but reduced-fat, reduced-energy lunch, and an iso-energetic reduced-fat lunch in 32 normal-weight men and women, age 35-55. Hunger and satiety were scored during and after the lunches, and their relationship to diet-induced thermogenesis was assessed. Diet-induced thermogenesis was relatively higher after the reduced-fat, reduced-energy lunch compared to the full-fat lunch (6.7% vs. 5.2%; p < 0.05). The respiratory quotients were significantly lower after the full-fat lunch than after the 2 reduced-fat lunches (p < 0.05). After the iso-energetic reduced-fat lunch, hunger scores were significantly reduced and satiety scores significantly increased (p < 0.05) until 1800 h. compared to the other 2 lunches. Satiety scores were positively related to the magnitude of diet-induced thermogenesis expressed as an absolute increase in metabolic rate during and after the meal. We conclude that hunger and satiety scores, substrate utilization, and diet-induced thermogenesis showed clear and different short-term responses to diets that differed with respect to the percentage energy from fat and/or the energy content of the meal.

The role of macronutrient selection in determining patterns of food intake in obese and non-obese women.

OBJECTIVE: Examination of the role of macronutrient selection in determining patterns of food intake in obese and non-obese women. DESIGN: Inventory: food intake diaries of two weekdays and one weekend day; EXPERIMENT randomized. SETTING: Inventory: in daily life. EXPERIMENT: department of Human Biology, University of Limburg. SUBJECTS: 68 subjects: 34 obese and 34 non-obese, age 20-50 years, selected based on accurate completion of food intake diaries (< 10% underreporting); a sub-sample of 32 (16 obese and 16 non-obese) was assigned to the experiment. INTERVENTIONS: An ample choice of food items consisting of mainly one macronutrient each were offered 4 and 6 times per day, with different macronutrient compositions per day, ranging from 1-77 en% fat, 3-45 en% protein, and 19-96 en% carbohydrate. RESULTS: Selection, namely food choice that differs from random consumption, took place at breakfast in favour of carbohydrate, and at dinner in favour of fat. Habituation, namely a decreased response on the same stimulus, occurred after the fourth exposure to a single macronutrient buffet. For protein this was expressed as a significantly increased satiety score per kJ ingested; for fat as a significant drop in hedonic value; for carbohydrate as a significantly increased desire for a different taste, all (P < 0.05). Compensation, i.e. a correction afterwards for an earlier unusual macronutrient composition, resulting in a close to usual macronutrient composition of 24 h food intake, occurred at dinner, for a previous unusually low fat and high carbohydrate intake. CONCLUSIONS: A pattern of macronutrient intake was achieved by selection and compensation. Habituation occurred at the fourth exposure of a single macronutrient.

Energy intake adaptation of food intake to extreme energy densities of food by obese and non-obese women.

OBJECTIVE: Examination of energy intake in relation to energy density of food in obese and non-obese women. Assessment of energy and macronutrient intake over a day. DESIGN: Controlled food intake diaries of two weekdays and one weekend day. SETTING: Daily life, with visits to the department of Human Biology, State University of Limburg. SUBJECTS: 96 women: 68 subjects: 34 obese and 34 non-obese were matched for age (20-50y) and were selected based on completing the food intake diaries accurately, i.e. underreporting < 10% of their estimated energy intake. RESULTS: The obese women showed a food intake distribution of 24 en% (0-7.5 kJ/g), 52 en% (7.5-15 kJ/g) and 24 en% (15-22.5 kJ/g), with a macronutrient composition of C/P/F: 39/17/44 en%. (Significantly different from the values of non-obese (P = 0.007) and of the Dutch food guidelines values (P = 0.008)). Non-obese women showed a food intake distribution of 38 en% (0-7.5 kJ/g), 49 en% (7.5-15 kJ/g), 13 en% (15-22.5 kJ/g), with a macronutrient composition of C/P/F: 46/17/37 en%. Energy intake per meal increased from 1.2 or 1.3 MJ to 4.1 or 4.5 MJ over a day. CONCLUSIONS: In obese women food intake was adapted to extreme energy densities of the food and in non-obese women food intake was overadapted to extreme energy densities. Energy intake per meal increased during the day.