The problem of obesity is multifactorial and prevention of weight gain can theoretically be achieved by changing the imbalance between energy consumed and spent. However, complex behavioral and social factors, including environments that promote unhealthy food choices and discourage physical activity are thought to be contributing to the imbalance driving the obesity epidemic population-wide. Ecological models based on the principle that health behaviors are influenced by various levels, indicate that the environment has a significant effect on diet, physical activity and obesity. Neighborhood-specific environmental factors and urban expansion have been associated with overweight and obesity among adults, and the lack of pedestrian amenities, difficult destinations, poorly connected street patterns, and perceptions of neighborhood safety have been hypothesized to contribute to reduced physical activity and the development of obesity.
Obesity and diabetes have become so inseparable that they are like ‘Siamese twins’. Evidence from several studies indicates that obesity and weight gain are associated with an increased risk of diabetes. Body mass index (BMI
) and weight gain are risk factors for diabetes. BMI
is one of the strongest predictors of diabetes, and previous studies have shown that changes in BMI
related to population-level changes foreshadow diabetes. For each increase of 1 kg in weight measured, the risk of diabetes increased 4.5% in a sample of US adults.
Lifestyle intervention programs, including exercise and healthy diet, are an option for the treatment and control of obesity and type 2 diabetes, and have been known to have beneficial effects on whole-body metabolism leading, in particular, to increased sensitivity to insulin. Obesity is associated with increased risk of various diseases and early mortality. In obese individuals, a low level of physical fitness is a better predictor of all-cause mortality than cholesterol levels, smoking, and blood pressure, and is similar to having had a previous cardiovascular event. Exercise training has many benefits on cardiovascular and metabolic diseases, including lowering blood pressure, plasma lipoprotein and triglyceride levels, and improvements in glycemic control, insulin sensitivity, vascular structure and endothelial function.
The goal of exercise programs and lifestyle modification is to combine education, food awareness, supervised physical activity and social support to help participants make lifestyle changes permanent. Physical exercise increases sensitivity to insulin and results in lower fasting insulin concentrations. Studies using the euglycemic-hyperinsulinemic clamp demonstrate that for the same circulating insulin concentration, the glucose elimination rates are higher and the rates of endogenous glucose production are lower in exercise-trained individuals. This benefit can be maintained in those who exercise throughout their lifetime; athletes have a master glucose and insulin response similar to test oral glucose tolerance as young athletes, and a significantly better response than insulin sedentary young. Therefore, physical training has a positive effect on insulin sensitivity, availability of glucose and insulin secretion in normal glucose-tolerant subjects.
Exercise training also increases whole-body, insulin-mediated glucose disposal in obese type 2 diabetics. The clinical profiles of individuals relatively newly diagnosed with glucose intolerance or diabetes successfully improved with the use of intervention programs of exercises. In larger studies however, patient compliance is a major challenge, especially because obesity itself, as with other associated common diseases, makes regular exercise programs both difficult and unsafe. One obstacle to exercise programs is that successful implementation of exercise and lifestyle modification programs in patients with long-term illness or complications can be challenging. However, lifestyle changes can be successful in patients with longer-term disease. Thus, lifestyle modification programs are an effective treatment option to reduce the risk factors associated with obesity and diabetes, even in patients who have not responded to conventional therapy.
Excess body fat is associated with a deterioration of glucose utilization and promotes development of type 2 diabetes, especially in those with a genetic predisposition to the disease. It is also well established that reduction of excess body fat improves insulin sensitivity and can prevent the conversion of diabetes. In people with overt diabetes, weight loss generally improves glycemic control and associated metabolic disturbances.
Among the pharmacologic agents that are used for the treatment of type 2 diabetes, metformin has a modest effect in reducing weight and is regarded as the drug of choice for oral pharmacotherapy adjuvant in the diabetic obese. GLP-1 analogues produce greater weight loss compared with metformin and should be considered in selected patients for both glycemic control and weight loss. Some studies also suggest that inhibitors of DPP-4 acarbose can induce modest weight reduction in such patients. In contrast, treatment with sulphonylurea and insulin is often accompanied by substantial weight gain that should be considered when these drugs are used. Another approach to improve metabolic control in obese type 2 diabetic patients is the use of agents for weight reduction. Serotonin and norepinephrine inhibitor sibutramine promotes weight loss that subsequently leads to better glycemic control. Orlistat, a lipase inhibitor, is also able to improve metabolic control in these patients due to their potential to reduce weight. As obesity remains a therapeutic challenge in most patients with type 2 diabetes, the weight control drugs may represent an alternative or supplement to antidiabetic agents. Furthermore, the weight control agents have the additional advantage that they have favorable effects on associated cardiovascular risk factors.
Changes in diet have a major impact on risk factors for coronary disease. The Adult Treatment Panel III (ATP III) recommends a multifaceted approach to lifestyle risk reduction of coronary heart disease, including the following:
get 50% to 60% of energy from carbohydrates, emphasizing whole grains, cereals, fruits and vegetables, reduce the saturated fat
Pregnancy causes difficulty in diabetes control. During pregnancy in the fasting state there is accelerated starvation because of the transfer of energy from mother to baby, and insulin resistance from, placental hormones causes postprandial hyperglycemia. Pregnancy can also worsen diabetic retinopathy and diabetic nephropathy because of the increase in growth factors from placental hormones during pregnancy.
Pregnancy increases complications for both mother and baby. For mothers with diabetes there will be increased risk of toxemia of pregnancy, pyelonephritis, hydraminios and cesarian delivery. For babies there will be increased risk of perinatal mortality, spontaneous abortion, congenital malformation, macrosomia, intra-uterine growth retardation (IUGR), intrauterine fetal death, respiratory distress syndrome, hypoglycemia, hypocalcemia and hypomagnesemia, hyperviscosity, hyperbilirubinemia, cardiomyopathy, and long-term consequences such as altered neuropsychological development, obesity and diabetes mellitus.
The targets for blood glucose during pregnancy are: at fasting less than 90 mg/dL, pre-prandial less than 95n mg/dL, at 1 hour postprandial less than 140 mg/dL and at 2 hours post-prandial less than 120 mg/dL
Every pre-gestational diabetes patients need insulin therapy and diet control during pregnancy. Regarding the prandial insulin, apart from conventional regular insulin, rapid acting insulins may be used during pregnancy. For basal insulin only NPH insulin
is generally recommended. For patients with gestational diabetes, diet and exercise is the mainstay of treatment, if the blood glucose is not controlled despite lifestyle changes, insulin should be started to bring the glucose levels to goal. In some patients who are unable to use insulin, metformin or glibenclamide may be considered as an alternative therapy.
For diabetic patients who are younger than 35 years without evidence of hypertension, coronary artery disease, nephropathy, retinopathy, or other vascular disease, using the combined oral contraceptive pill can be appropriate. For other diabetic patents, with the above mentioned contraindications, using of intrauterine devices or progestin-only contraception is recommended.