Background:Abdominal obesity is associated with coronary risk, although causality is not well established. Objective: In an obese Mediterranean population, we measured the fatty acid composition of adipose tissue, its relation with dietary fatty acids and central fat deposition, and its influence on plasma lipids and insulin. Design: Adipose tissue samples were obtained from 84 obese patients (29 men, 55 women) aged 30-70 y (body mass index, in kg/m 2 : 27-35). We measured concentrations of insulin and lipids in plasma and fatty acids in subcutaneous, omental, and perivisceral fat. Dietary fatty acid intake was assessed with a 7-d diet record. Results: The population studied was normolipidemic and normoinsulinemic. There were important differences in fatty acid composition between tissue sites: saturated fatty acids were higher and monounsaturated fatty acids were lower in perivisceral than in subcutaneous fat (P < 0.05). Significant correlations were found for oleic, linoleic, ␣-linolenic, and total nϪ6 polyunsaturated fatty acids between the subject's habitual diet and adipose tissue composition. Oleic and nϪ3 fatty acids from adipose regions were negatively correlated with apolipoprotein B and triacylglycerols; adipose tissue 22:1nϪ9, 20:2nϪ6, stearic acid, and eicosapentaenoic acid were positively correlated with HDL and apolipoprotein A; and adipose tissue myristic acid was negatively correlated with apolipoprotein A (P < 0.05). Central obesity was positively associated with nϪ6 polyunsaturated fatty acids and inversely associated with monounsaturated fatty acids and nϪ3 polyunsaturated fatty acids in adipose tissue (P < 0.05). Conclusion: The differences found in the composition and metabolism of perivisceral, omental, and subcutaneous fats may indicate that their atherogenic capacities also differ.Am J Clin Nutr 2001;74:585-91.

There is a high prevalence of overweight and obesity in the adolescent population studied (48.2% in boys and 30.7% in girls). The study shows an association between overweight and obesity and nutrient intake and activity level.

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Spanish adolescents presented different sedentary patterns according to age, gender and SES. Boys reported more time engaged in electronic games, whereas girls reported more time studying. Parental occupation had more influence than parental education on the time spent in sedentary behaviours.

The aim of the present study was to investigate the maternal-fetal transport, incorporation, and effects on liver delta-6 fatty-acid desaturase activity of dietary trans fatty acids in pregnant rats. Three groups of six rats each were fed three experimental diets containing approximately 0%, 15%, and 30% of trans fatty acids but containing the same proportion of linoleic (18:2 n-6) and a-linolenic (18:3 n-3) acids for 10 wk. On d 20 of pregnancy, the animals from each group were killed. We determined the fatty acid profiles in plasma, brain, and liver microsomes of pregnant rats, as well as in placenta and fetal liver and brain. No changes were found in the number of fetuses of the pregnant rats. Trans fatty acids were incorporated in high concentrations in placenta and in maternal and fetal tissues, except brain, strongly elevating the linoleic acid proportion and lowering that of docosahexaenoic acid. The delta-6 fatty-acid desaturase activity in the liver microsomes of the pregnant rats was inhibited by trans isomers. In conclusion, high intakes of trans fatty acids partially inhibit liver delta-6 fatty-acid desaturase in pregnant rats, which may explain, in part, the low concentrations of docosahexaenoic acid in pregnant and fetal tissues. However, the fatty acid composition of both fetal and pregnant rat brain remains mostly unaffected regardless of the dietary trans fatty acid content.

Summary Objectives: To evaluate the weight loss of a dietary/behavioural weight reduction programme and causes for drop‐out. Methods: 90 overweight patients with a mean weight of 79±17 kg and BMI of 28.8±5 kg m−2 who attended a clinic to lose weight were subjected to a dietary/behavioural weight reduction programme. Treatment consisted in behavioural therapy with nutritional education, diet and physical activity. To evaluate the effectiveness of the treatment the following were considered: percentage of individuals who completed the treatment, weight reduction, average rate of weight reduction and percentage of individuals who completed the follow‐up period. To determine the reasons for dropping out, an open‐ended questionnaire was administered by telephone by trained clinical personnel. Results: 43% of patients completed the treatment, mean weight loss was 9 kg and the mean rate of weight loss was 0.8 kg week−1. Reasons for dropping out were: vacations (23%), search for faster or fad diets (23%), social pressures (11%), excessive duration of the treatment (9%); failure to understand the diet (9%); differences within the group (7%); and illness and pregnancy (7%). Conclusions: Dietary/behavioural treatment is effective in clinical practice and especially adequate for men and young women. It is not satisfactory for individuals with very high BMI (> 35 kg m−2). Vacations, social causes and the search for ‘miracle’ diets were the principal reasons for drop‐out.

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This study was designed to investigate the effects of three diets with different levels of trans fatty acids and the physiologic status on the physicochemical properties and enzymatic activities of liver microsomes and mitochondria. Three groups of 10 female weaning rats each were fed for 10 wk one of three diets differing in their trans fatty acid contents (Control, 0 mol/100 mol total fatty acids; high, 14.5 mol/100 mol; very high, 30 mol/100 mol). At the onset of adult life (10 wk of age), they were mated. Six rats in each group were killed at the end of gestation (Pregnant rat groups). The four remaining pregnant rats continued to receive their experimental diets until weaning of their litters. Six pups from the litters for each group (3 males and 3 females) were selected and fed the same experimental diet as the dams from wk 3 to 10 of age (2nd generation virgin groups) and then killed. Trans fatty acid levels in liver microsomes and mitochondria rose in parallel with the dietary trans fatty acid content, whereas saturated fatty acids dropped in both organelles with increasing trans fatty acids. Pregnant and 2nd generation adult rats fed trans isomers also had lower levels of cholesterol and a lower cholesterol/phosphorus ratio in their liver microsomes compared with controls. A significant interaction between diet and pregnancy was detected in the activities of delta6-desaturase and glucose-6-phosphatase in liver microsomes. Dietary trans fatty acids decreased the activities of both enzymes but only in pregnant rats. No differences in the fluorescence anisotropy of membranes or the enzymatic activities in liver mitochondria were observed. In conclusion, dietary trans fatty acids significantly lowered cholesterol and the cholesterol/phosphorus ratio in liver microsomes. This effect might contribute to low delta6-desaturase and glucose-6-phosphatase activities in liver microsomes of pregnant rats.