Apport lipidique et prise de poids. Aspects quantitatifs - Un débat

From a quantitative point of view the role of dietary fat in weight gain apparently seems clear, but its accountability in obesity pathogenesis, for individuals or population, is not definitively established.This concern may be divided in four sections:

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On a physiopathological point of view, experimental data show that fats are able to increase energy density and food intake and to increase lipogenesis.

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On an epidemiological point of view the data are more conflicting. An higher fat intake was associated to the obesity epidemic, its decrease did not stopped it, and that suggest the role of others lifestyle patterns including physical activity.

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On a clinical point of view the studies are far from a consensus, but it is true that they focuse on the role of familial, educative and genetic factors. But really a fat excess can sensitive the effect of inactivity. Total energy intakes seem a main issue.

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The fat reduction is not sufficient to induce a weight loss or to prevent a weight gain. We must act on each component of energy balance. In insulin-resistant subjects the fat reduction without weight-loss does not seem favourable on cardiovascular risk.

Finally the total fat intakes cannot be considered as the cause of obesity but they may participate to the weight gain in some conditions. Qualitative aspects, and therefore fatty acids, must be also considered.