1.
Diet or exercise: what is more effective in preventing or reducing metabolic alterations?
Bo, S, Ciccone, G, Guidi, S, Gambino, R, Durazzo, M, Gentile, L, Cassader, M, Cavallo-Perin, P, Pagano, G
European journal of endocrinology. 2008;(6):685-91
Abstract
OBJECTIVE/DESIGN The influence of diet and exercise on metabolic syndrome is controversial since fit individuals might also eat healthier foods. We evaluated the association of diet/exercise variation with reductions in metabolic variables and C-reactive protein (CRP) values in the experimental and control arms of a 1-year randomized lifestyle intervention trial performed in patients with multiple metabolic abnormalities. METHODS A prospective study of 169 cases and 166 controls after a lifestyle intervention was performed. RESULTS In the intervention group, 15/169 (8.9%), 63/169 (37.3%), and 70/169 (41.4%) reached only dietary, only exercise, and dietary/exercise targets respectively. Reductions in weight, body mass index (BMI), and waist were significant only in patients who increased exercise. Most controls did not reach any target (131/166, 78.9%), while only few patients reached only dietary (13/166, 7.8%), only exercise (5/166, 3.0%), and dietary/exercise targets (17/166, 10.2%). Weight, BMI, and waist reduction was more pronounced in those reaching the exercise target. In the whole cohort, increased exercise was inversely associated with weight, BMI, waist, and CRP, increased saturated fat was directly associated with weight, BMI, waist, and diastolic pressure variations, while increased fiber intake was inversely associated with glucose values in a multiple regression model. After adjusting for waist changes, the associations between exercise and CRP (beta=-0.023; 95% CI -0.028 -0.017; P<0.001) and the associations between fiber and glucose (beta=-0.022; -0.031 -0.013; P<0.001) remained significant. CONCLUSIONS Independent of weight reduction, exercise level and fiber intake are inversely associated with CRP and fasting glucose values respectively. Change in lifestyle may lower inflammation and prevent metabolic deterioration.
2.
A low-carbohydrate as compared with a low-fat diet in severe obesity.
Samaha, FF, Iqbal, N, Seshadri, P, Chicano, KL, Daily, DA, McGrory, J, Williams, T, Williams, M, Gracely, EJ, Stern, L
The New England journal of medicine. 2003;(21):2074-81
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Abstract
BACKGROUND The effects of a carbohydrate-restricted diet on weight loss and risk factors for atherosclerosis have been incompletely assessed. METHODS We randomly assigned 132 severely obese subjects (including 77 blacks and 23 women) with a mean body-mass index of 43 and a high prevalence of diabetes (39 percent) or the metabolic syndrome (43 percent) to a carbohydrate-restricted (low-carbohydrate) diet or a calorie- and fat-restricted (low-fat) diet. RESULTS Seventy-nine subjects completed the six-month study. An analysis including all subjects, with the last observation carried forward for those who dropped out, showed that subjects on the low-carbohydrate diet lost more weight than those on the low-fat diet (mean [+/-SD], -5.8+/-8.6 kg vs. -1.9+/-4.2 kg; P=0.002) and had greater decreases in triglyceride levels (mean, -20+/-43 percent vs. -4+/-31 percent; P=0.001), irrespective of the use or nonuse of hypoglycemic or lipid-lowering medications. Insulin sensitivity, measured only in subjects without diabetes, also improved more among subjects on the low-carbohydrate diet (6+/-9 percent vs. -3+/-8 percent, P=0.01). The amount of weight lost (P<0.001) and assignment to the low-carbohydrate diet (P=0.01) were independent predictors of improvement in triglyceride levels and insulin sensitivity. CONCLUSIONS Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels, even after adjustment for the amount of weight lost. This finding should be interpreted with caution, given the small magnitude of overall and between-group differences in weight loss in these markedly obese subjects and the short duration of the study. Future studies evaluating long-term cardiovascular outcomes are needed before a carbohydrate-restricted diet can be endorsed.