We need body fat to protect our organs, keep us warm, and for a number of basic bodily functions, but carrying extra body fat is a risk factor for dozens of health complications, disorders, and chronic diseases. On one hand, it’s simple to point to excess calories eaten—no matter the food they are from—as the culprit because body fat functions as storage when food is consumed beyond immediate needs. It’s an evolutionary process: our ancestors’ ability to survive famine and short periods of limited edible food availability by storing calories, our cells needed fuel source, is because of this process and reliance on body fat. For most people in the 21st century the issue is no longer a shortage of food, but an excess. And the reason some are more likely to put on weight in the form of body fat is exceedingly complex.
Body fat can be measured in a number of different ways including underwater weighing or measured via calipers by a trained professional. One of the most commonly used statistics is called body mass index (BMI) which is a calculated ratio of a person’s height and weight. Search for a BMI calculator online to figure out your own statistic. The benefits of BMI are that it can be calculated quickly with minimal tools and the resulting number can be put in a chart to determine if someone is overweight (BMI between 25 and 29.9) or obese (BMI >30). This simple calculation and charting can estimate the body fat percentage of most individuals with reliable precision, but it has obvious shortcomings: it doesn’t measure muscle mass nor does it discern how the body fat is distributed— an important consideration when determining health risks.
Body fat distribution is often dichotomized into apple shape or pear shape. A pear is larger on the bottom and narrow toward the top representing fat that accumulates more in the hips and thighs (the bottom of the pear) than the stomach and waist. An apple shape is more rounded and describes fat accumulation in the stomach region and around the waist. It also called central obesity. Research suggests that apple shape / excess stomach fat is a greater risk factor than pear shape / excess thigh and hip fat.
Central obesity is one of a group of conditions, along with increased blood pressure, high fasting blood glucose levels, and abnormal cholesterol or triglyceride levels that, when occurring together, are called metabolic syndrome and significantly increase one’s risk for cardiovascular diseases such as heart disease, stroke and type-2 diabetes. One in three US adults is pre-diabetic, meaning they have elevated blood sugar levels, but are not (yet!) in the range that triggers diagnosis of diabetes. Carrying excess body fat, especially around the waist in the apple shape, raises blood glucose levels. After a meal, carbohydrates are turned into glucose and our pancreas produces insulin to transport it from the blood to the cells that need it, via insulin receptors. The excess and larger fat cells that are present in obesity reduce the efficacy of this process and cause insulin resistance, which leads to high blood glucose numbers and, if unchecked, type-2 diabetes.
This condition is concerning because type-2 diabetes shortens life spans by 20 years, on average, as heart attacks are the leading cause of death for diabetics. The good news is that nutrition interventions can prevent and treat obesity, metabolic syndrome, type-2 diabetes, and heart disease.
It’s important to remember that being overweight or obese is just one of many risk factors for chronic diseases; it is not the only one. For example being sedentary is a risk factor but exercising regularly, even without weight loss, eliminates that risk. Eating a diet that is low in saturated fat and high in fiber and phytochemicals from whole grains, legumes, fruits, and vegetables is another changeable risk factor, regardless of weight loss, though a diet high in these foods is likely to help with losing weight. Additionally, improving biometrics such as high cholesterol or high blood glucose, can be done with just moderate weight loss in the range of 3-5% of total body weight. It’s a misnomer that one needs to be an ‘ideal’ weight to reap the benefits of weight loss.
As we age our metabolism slows down and it is more difficult to maintain a healthy body weight. Small weight gain can be expected, but if you have gained significant weight or your BMI has increased to a new category, consider discussing weight loss options with your doctor or a registered dietitian. It is, obviously, much easier to put on weight than to lose it, but small adjustments in caloric intake can halt the process of body fat accumulation and starting an exercise routine, no matter how simple, can burn off those extra calories currently stored as body fat.
—Matt Ruscigno, MPH, RD