Objective: To test the hypothesis that a diet containing many sweet foods is associated with poor weight loss after gastroplasty.
Subjects and methods: 375 severely obese subjects followed for 2 y after vertical banded gastroplasty or gastric banding; 34 subjects followed after gastric bypass.
Results: Total energy and all macronutrients were reduced 2 y after surgery. Sweet foods were less reduced than other foods, resulting in a relative increase of sugar intake. At 2 y a high relative intake of sugar and fat was associated with a low energy intake and a large weight reduction in the gastroplasty group. In the highest quartile of mono+disaccharide intake (> 142 g) weight loss was 29.9 kg compared to 25.1 kg in lowest quartile (> 72 g). Absolute and relative sugar intake before surgery did not predict weight outcome. At 6 months, i.e. during a period of active weight reduction, energy intake was significantly related to weight loss.
Conclusion: Gastroplasty patients who continue selecting sweet foods appear to maintain lower energy intakes and lose more weight. However the associations are unlikely to be causal but probably indicative of changes in other aspects of the diet, eg exclusion of regular meals. Since large weight losses are most likely to be associated with low quality diets these results highlight the need for supplementation therapy of gastroplasty patients. Finally the lack of association between presurgical sugar intake and subsequent weight loss brings into question the surgical practice of selectively assigning sweet eaters to gastric bypass.