Nutritional influences on lipogenesis and thermogenesis after a carbohydrate meal

Abstract

In vivo lipogenesis and thermogenesis were studied for 24 h after ingestion of 500 g of carbohydrate (CHO) in subjects who had consumed either a high-fat, a mixed, or a high-CHO diet during the 3-6 days preceding the test. CHO oxidation and conversion to fat was significantly less in the high-fat diet group (222 +/- 5 g) than in the mixed (300 +/- 13 g) or high-CHO diet (331 +/- 7 g) groups, resulting in a greater glycogen storage in the high-fat (278 +/- 6 g) than in the other two groups (197 +/- 11 and 170 +/- 2 g). Net lipogenesis occurred sooner and lasted longer in the high-CHO group, amounting to 0.8 +/- 0.5, 3.4 +/- 0.6, and 9 +/- 1 g of lipid synthesized in the high-fat, mixed, and high-CHO groups, respectively. The thermic effect of the CHO load was 5.2 +/- 0.5% on the high-fat, 6.5 +/- 0.4% on the mixed diet, and 8.6 +/- 0.4% on the high-CHO diet. Significant relationships were demonstrated between the postabsorptive nonprotein respiratory quotient and net lipogenesis after the CHO load (r = 0.82) and between net lipogenesis and the increase in energy expenditure (r = 0.71). It is concluded that the antecedent diet influences the amount of net lipogenesis and the magnitude of thermogenesis after a large CHO test meal. However, lipogenesis remains too limited even after such large CHO intakes to cause an increase in the body's fat content.

Concept of fat balance in human obesity revisited with particular reference to de novo lipogenesis

“…The logical question related to this issue is how the direct energy 'cost of oxidation' of a substrateFa process that aims at providing ATP's rather than consuming itFcould be greater than the cost of transformation of the same substrate into another substrate. Another issue which contradicts Acheson's assumption is that the magnitude of overall DNL (estimated by indirect calorimetry) has been found to be positively and highly significantly correlated (r ¼ 0.71) to the thermic effect of food in a situation in which there is no net fat storage due to DNL over 24 h. 7 The slope of the regression line suggests that a net lipogenesis of 10 g/day increases the absolute thermogenesis by 70%.…”

Dietary factors in relation to weight change among men and women from two southeastern New England communities

“…8 This disequilibrium has been demonstrated in a number of experimental studies. 9,10 In contrast, observations from some crosssectional studies have shown an inverse association between energy intake and obesity. 11,12 One explanation for the inverse association is an underestimation of food intake by obese individuals.…”

De novo lipogenesis in humans: metabolic and regulatory aspects

“…A number of studies (Acheson et al, 1982(Acheson et al, , 1984 have con®rmed that a single meal containing large amounts of CHO energy (up to 500 g CHO) in previously weight stable subjects does not cause NP RQ to rise above 1.0. This has been interpreted as evidence against a quantitatively important role for DNL in the dayto-day storage of surplus CHO energy; also, storage as glycogen was concluded to represent the fate of excess dietary CHO.…”