Objective: To investigate the effect of addition of modified guar gum (GG) to a low-energy semisolid meal on appetite and body weight (BW) loss.
Subjects: Twenty eight mainly overweight male volunteers (age, 19-56 y; body mass index, 29+/-2 kg x m(-2); BW, 89.4+/-9.2 kg).
Design: Baseline of one week with self-selected diet. Three treatments of 2 weeks with a low-energy diet divided over three times a day, consisting of a semisolid meal with (SSM+) or without GG (SSM) or a solid meal (SM) with the same energy content (947 kJ) and macronutrient composition, and a dinner of the subject's own choice. Washout periods lasted 4 weeks.
Results: Compared to baseline values, reduction in energy intake and BW loss were similar for SSM+, SSM and SM. Appetite (hunger, desire to eat or estimation of how much one could eat) was increased in SSM and in SM compared to baseline, but not in SSM+. Satiety and fullness in SSM+, SSM and SM were similar to baseline. Any intervention was more effective on BW loss when it took place the first time compared to the second and third times (2.6+/-0.2 kg, 1.7+/-0.2 kg and 1.1+/-0.2 kg, respectively; P<0.001). The SM-SSM+-SSM sequence was more effective on BW loss compared to the SSM+-SSM-SM sequence (5.6+/-1.0 and 2.5+/-0.6 kg, respectively; P<0.05).
Conclusion: All the three treatments were equally effective with respect to BW loss. GG addition to a semisolid meal prevented an increase in appetite, hunger and desire to eat, which increase was present in the other treatments. However, differences between treatments were not statistically significant. The order effect shows that repeated 2-week bouts of dieting become increasingly ineffective. The sequence SM-SSM+-SSM was more effective than the sequence SSM+-SSM-SM, probably because compliance was relatively higher with the SSM+ or SSM diet, and compliance decreased towards the end of the complete experiment.