Effects of energy content and energy density of pre-portioned entrées on energy intake.

Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on 1 day a week for 4 weeks. Each meal included a compulsory, manipulated pre-portioned entrée followed by a variety of unmanipulated discretionary foods that were consumed ad libitum. Across conditions, the entrées were varied in both energy content and ED between a standard level (100%) and a reduced level (64%). Results showed that in men, decreases in the energy content and ED of pre-portioned entrées acted independently and added together to reduce daily energy intake (both P < 0.01). Simultaneously decreasing the energy content and ED reduced total energy intake in men by 16% (445 ± 47 kcal/day; P < 0.0001). In women, the entrée factors also had independent effects on energy intake at breakfast and lunch, but at dinner and for the entire day the effects depended on the interaction of the two factors (P < 0.01). Simultaneously decreasing the energy content and ED reduced daily energy intake in women by 14% (289 ± 35 kcal/day; P < 0.0001). Both the energy content and ED of pre-portioned entrées affect daily energy intake and could influence the effectiveness of such foods for weight management.

Hidden vegetables: an effective strategy to reduce energy intake and increase vegetable intake in adults.

BACKGROUND: The overconsumption of energy-dense foods leads to excessive energy intakes. The substitution of low-energy-dense vegetables for foods higher in energy density can help decrease energy intakes but may be difficult to implement if individuals dislike the taste of vegetables. OBJECTIVE: We investigated whether incorporating puréed vegetables to decrease the energy density of entrées at multiple meals reduced daily energy intakes and increased daily vegetable intakes. DESIGN: In this crossover study, 20 men and 21 women ate ad libitum breakfast, lunch, and dinner in the laboratory once a week for 3 wk. Across conditions, entrées at meals varied in energy density from standard versions (100% condition) to reduced versions (85% and 75% conditions) by the covert incorporation of 3 or 4.5 times the amount of puréed vegetables. Entrées were accompanied by unmanipulated side dishes. Participants rated their hunger and fullness before and after meals. RESULTS: Subjects consumed a consistent weight of foods across conditions of energy density; thus, the daily energy intake significantly decreased by 202 ± 60 kcal in the 85% condition (P < 0.001) and by 357 ± 47 kcal in the 75% condition (P < 0.0001). Daily vegetable consumption significantly increased from 270 ± 17 g of vegetables in the 100% condition to 487 ± 25 g of vegetables in the 75% condition (P < 0.0001). Despite the decreased energy intake, ratings of hunger and fullness did not significantly differ across conditions. Entrées were rated as similar in palatability across conditions. CONCLUSIONS: Large amounts of puréed vegetables can be incorporated into various foods to decrease the energy density. This strategy can lead to substantial reductions in energy intakes and increases in vegetable intakes. This trial was registered at clinicaltrials.gov as NCT01165086.

Increasing the protein content of meals and its effect on daily energy intake.

High-protein preloads have been shown to enhance satiety, but little is known about the satiating effects of protein in more typical situations when meals are consumed ad libitum. To investigate the effects of protein in amounts commonly consumed over a day, a crossover study was conducted in 2008. In this experiment, 18 normal-weight women consumed ad libitum lunch and dinner entrées 1 day a week that were covertly varied in protein content (10%, 15%, 20%, 25%, or 30% energy). Entrées were manipulated by substituting animal protein for starchy ingredients and were matched for energy density, fat content, palatability, and appearance. Unmanipulated breakfasts and evening snacks were consumed ad libitum. Participants rated their hunger and fullness before and after meals as well as the taste and appearance of entrées. Data were analyzed using a mixed linear model. Results showed that mean 24-hour protein intake increased significantly across conditions, from 44±2 g/day in the 10% protein condition to 82±6 g/day in the 30% condition. Daily energy intake did not differ significantly across the 10% to 30% protein conditions (means 1,870±93, 1,887±93, 1,848±111, 1,876±100, and 1,807±98 kcal in the 10%, 15%, 20%, 25%, and 30% energy groups, respectively). There were no significant differences in hunger and fullness ratings across conditions or in taste and appearance ratings of the manipulated entrées. This study showed that varying the protein content of several entrées consumed ad libitum did not differentially influence daily energy intake or affect ratings of satiety.