By Stephanie Leveene, medwireNews Reporter
Reducing fat intake leads to reduced body weight, body mass index (BMI), and waist circumference in adults over the long term, even when weight loss is not the intended outcome, according to a meta-analysis published in the BMJ.
From a public health perspective, these findings give credence to efforts to decrease total fat intake to less than 30% of energy intake, with the potential to reduce related mortality.
"The effect on health of an individual reducing his or her body weight by 1.6 kg is likely to be small, but the effects of a whole population doing so would be noticeable," say Lee Hooper (Norwich Medical School, University of East Anglia, UK) and co-authors.
The World Health Organization (WHO) Nutrition Guidance Expert Advisory Group subgroup on diet and health assessed the relationship between total fat intake and body weight with a view to updating WHO guidelines. Hooper and colleagues assessed 33 controlled trials that measured interventions to reduce total fat intake but were not specifically weight loss studies. Study durations were a minimum of 26 weeks and a maximum of 8 years.
Participants in these studies were randomly assigned to participate in one of two arms: lower fat intake or usual fat intake. The mean effect of the decreased amount of total fat intake was a weight loss of 1.57 kg in the lower-fat group compared with controls. Each 1% reduction in energy was associated with a 0.19-kg reduction in body weight.
Significant reductions in BMI (−0.51 kg/m2) and waist circumference (−0.30 cm) were also seen in those with lower fat intake, as well as improvements in blood pressure and total cholesterol.
Hooper et al say that similar effects were noted in children and adolescents, but the sample size of that population was small.
They note that there is a need for high-quality trials examining the effect on body weight of reducing fat intake in children, especially in developing or transitional countries where total fat intake is more than 30% of energy.
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