Fat oxidation, body composition and insulin sensitivity in diabetic and normoglycaemic obese adults 5 years after weight loss

Abstract

OBJECTIVE:To investigate whether normal glucose-tolerant and type II diabetic overweight adults differ in response to weight regain with regard to substrate oxidation and metabolic parameters. METHODS: A total of 15 overweight-obese subjects: seven normal glucose tolerant (NGT) and eight with type II diabetes (DM) were restudied 5 y after significant weight loss. Prediet, after 28 days calorie restriction and at 5 y, subjects were characterised for weight, height, waist-to-hip ratio (WHR) and body composition by dual-energy X-ray absorptiometry. Fasting glucose, insulin, leptin and lipid levels were measured and subjects underwent euglycaemic-hyperinsulinaemic clamp (insulin 0.25 U/kg/h for 150 min). Indirect calorimetry was performed resting and in the final 30 min of the clamp. Dietary assessment was by 4-day dietdiary. RESULTS: Both NGT and DM groups regained weight at 5 y and were not different to prediet. Total body fat (%) and WHR were higher at 5 y compared to prediet in both groups. Fasting glucose was increased in NGT subjects at 5 y, and fasting insulin was higher in both groups at 5 y compared to prediet. Insulin sensitivity (GIR) was similar at 5 y compared to prediet, but at 5 y DM subjects were more insulin resistant than NGT subjects. At 5 y, both DM and NGT groups had significantly reduced basal fat oxidation and no significant suppression of fat oxidation with insulin. Clamp respiratory quotient levels at 5 y were significantly higher in NGT compared to DM subjects. CONCLUSION: Reduced basal fat oxidation, and reduced variation in substrate oxidation in response to insulin develop with fat regain and fasting hyperinsulinaemia in both NGT and DM obese adults.

The Effect of Type 2 Diabetes on Body Composition of Older Adults

“…Several small case-control studies among middle-aged persons found either no differences in fat distribution [18][19][20] or an unfavorable fat distribution with more truncal fat and less peripheral fat in persons with type 2 diabetes compared with healthy controls. 21,22 Fat distribution in older adults with type 2 diabetes was examined in a small casecontrol study.…”

Altered body composition in type 2 diabetes mellitus

“…Maiolo et al 6 , in a study of body composition and pulmonary function in matched type 2 diabetes and control groups of women reported more lean mass and nonsignificantly less fat mass in type 2 diabetes. Poynten et al 7 observed no difference in percentage TBF between weight and body mass index (BMI)-matched controls and subjects with type 2 diabetes. Studies that report fat as a proportion of total body weight often find subjects with type 2 diabetes to have higher percentage of fat.…”

“…[5][6][7] Studies that report fat as a proportion of total weight often find subjects with type 2 diabetes to have a higher proportion of body weight as fat. 8 In contrast, we found that after adjustment by regression for weight, height, race/ethnicity, sex and age, subjects with type 2 diabetes had less total fat mass and more lean mass than controls.…”

Study of the Metabolic Status by Complex Indirect Calorimetry and Bioimpedometry

“…It is also obvious that the criteria for correction of therapeutic rations in diabetics with type 2 disease and cardiovascular patients should be based on analysis of patients' metabolograms, body composition characteristics, and data of standard biochemical and hormone tests [2,4,8]. Final correction of therapeutic rations should be based on metabolograms at rest and metabolograms recorded under other physiological conditions, including exercise and test meals.…”

“…This principle is based on the fact that amino acid oxidation rate determines the protein requirements of the organism [5,6,10,11]. This assumption can be fully extrapolated to glucose and fatty acid oxidation rates.Study of oxidative metabolism by endogenous rates of glucose, amino acid, and fatty acid oxidation by indirect calorimetry at rest and during exercise provides a tentative evaluation of metabolic disorders in maladaptation and development of nutrition-dependent disease [7][8][9]. However, the oxidation rates of the main macronutrients should be converted to the units of body weight and its constituents, primarily fatty and lean weights, which fact is virtually neglected at present.…”