Are diets high in non-milk extrinsic sugars conducive to obesity? An analysis from the Dietary and Nutritional Survey of British Adults.

Restriction of dietary sugars is often advocated for weight control, alongside a reduced fat and energy intake. This project examined data from the Dietary and Nutritional Survey of British Adults (Gregory et al, 1990) to evaluate the associations between non-milk extrinsic (NME) sugars (as a percentage of food energy) and body mass index (BMI), energy intake and percentage energy from fat. The influence of dieting and potential under reporting on these relationships was also explored. BMI was inversely associated with percentage energy from NME sugars. The relationship was weak, but did not appear to be a mere artifact of dieting and/or under reporting. The well-recognized reciprocal relationship between sugars energy and fat energy was also seen with saturated, monounsaturated and polyunsaturated fatty acids, but not with trans fatty acids. As a result of the sugar : fat see saw effect, only 2% of men and women met the current dietary targets for both fat and NME sugars, suggesting that these may be incompatible on a practical level. These analyses suggest that high (NME) sugar diets appear to be weakly related to leanness rather than obesity, although the relationship is weaker than the inverse association between sugars and fat. It is hypothesized that overweight and diet-restrained individuals often choose to restrict NME sugars: a strategy which can result in a higher (proportional) fat diet and weight gain. Emphasis on reducing NME sugars intakes may be counterproductive to attempts to reduce proportional fat intake and body weight.