Obesity is a risk factor for cardiovascular disease and is associated with many comorbidities, including type 2 diabetes, hyperlipidemia, heart failure, and hypertension. Being overweight can limit your mobility, leading to falls or strains in everyday life and it may even lead to a decline in self-esteem. Obesity is also associated with decreased life span and mortality.
Obesity is the excess accumulation of body fat. The BMI, or, weight in kilograms divided by the square of the height in meters, correlates fairly well with body fat stores and is generally used to classify medical risk. The BMI can classify some older people as overweight (BMI 30.0–34.9 kg/m2) or obese (BMI ≥ 35.0 kg/m2) who actually do not have an excess of body fat. For example, if a person loses height as a result of vertebral compression fractures, his or her BMI would become higher, even with no change in weight or body fat. On the other hand, changes in body composition with age, including loss of muscle and an increase in fat, may not be reflected in the BMI, even if the person really does have too much body fat.
In older patients, the waist circumference may be more appropriate than the body mass index (BMI) as a measure of adiposity. The measurement should be made halfway between the iliac crest and the lower anterior ribs, with the patient standing, and at the end of expiration. The traditional standard for waist circumference is less than 89 cm (35 inches) for women and 102 cm (40 inches) for men. The waist circumference is as good as or even better than the BMI as a measure of excess adiposity in older adults. This is in part because of the age-dependent height decrease in older adults.
Percent body fat is another way to assess body fat. It is defined as the total weight of fat divided by total weight, and is measured in various ways. The traditional universal cutoffs for defining obesity by percent body fat are 25% in men and 35% in women. Unfortunately, most of the tests that measure percent body fat and differentiate visceral from subcutaneous fat are most often used only in research because they are relatively expensive.
Data suggests that being moderately overweight may offer a survival advantage in older people, but a body mass index of 30kg/m2 or higher does continue to be associated with many health risks. Weight loss in this age group should always take into account the benefits and risks of lifestyle interventions, drug therapy, and surgery. Lifestyle interventions with an emphasis on exercise and strength training can optimize their overall health and quality of life.
Intentional weight loss is very different from unintentional weight loss. In most cases, weight loss in older adults is unintentional and may indicate underlying disease and impending death. For example, those who lose weight unintentionally may have done so due to smoking, disability, cancer, and respiratory disease and not due to physical activity. Studies have shown an increase in life expectancy in older patients with type 2 diabetes mellitus who lost weight intentionally. In fact, moderate weight loss—just 5% to 10%—has been shown to improve cardiovascular risk factors, osteoarthritis, and type 2 diabetes.
Caution is advised in recommending weight loss solely on the basis of body weight, as studies have shown that the weight associated with maximal survival increases with age. Significant caloric restriction is often not recommended. Treatment for weight loss differs from that in the younger population primarily because of the importance of preventing loss of muscle. People of all ages who lose weight intentionally lose fat and, to a lesser extent, skeletal muscle. Older patients have already lost muscle mass, but further changes in body composition, especially a further reduction in muscle mass; can be limited by consuming about 1.0 g/kg of high-quality protein in the diet and by engaging in resistance training and weight training.
A regular exercise program is important for improving overall physical function, which can slow progression to frailty. Adding aerobic, endurance, and resistance training helps preserve fat-free mass, which otherwise tends to diminish during active weight loss. If you are unable to engage in physical exercise and there is importance in the need to lose weight, you may be able to talk to your physician about weight-loss drugs known as appetite suppressants or those that interfere with nutrient absorption. When assessing older adults, physicians should always review the drugs that are currently being taken. Those known to cause weight gain can include a few of the following:
If a different physician, such as a specialist, prescribed the original drug, he or she should be notified or consulted about any change. Always speak to your physician before undergoing major changes in your diet or exercise program. They can safely guide you and monitor your progress along the way.