What your waist line says about your health

This blog is the 4th in a series of 5 on the topic of metabolic syndrome risk factors.

Obesity is a complex disease which is associated with numerous other diseases and conditions including heart disease, certain cancers, stroke, diabetes and liver disease. It is closely linked to the presence of metabolic syndrome and often co-occurs with high cholesterol, high blood pressure and elevated blood glucose levels. Being overweight or obese was once a problem seen mainly in developed countries however in the past few decades it has become a global epidemic. 38% of the global population and 69% of the population in the United States are overweight or obese.

Having excess body fat is a simple way to define being overweight or obese. One common metric which is used to classify whether an adult is overweight or obese is the body mass index (BMI) which considers one’s weight and height. Overweight is a BMI equal to or greater than 25, whereas obesity is a BMI equal or greater than 30. Although it is a good tool for looking at a whole population, BMI is actually a poor way of assessing and managing an individual's risk of disease.

Being fat is bad for your health and the distribution of where that fat is situated in your body also matters. The medical evidence is clear that individuals with a larger waist have a higher risk of cardiovascular disease and premature death than those with slimmer waists. Larger waists come from having a higher amount of fat around organs inside the abdomen, also known as visceral fat.

Visceral fat surrounds the liver, intestines and other abdominal organs - it lies deep within our bodies beneath muscle. The other type of fat is subcutaneous fat which lies just beneath the skin (and above the muscle layer) - fat which you can pinch - and this is less dangerous for your health. 

So what is it that makes abdominal (visceral) fat such a strong risk factor for disease like cancer, stoke, heart attacks and diabetes? Visceral fat is very metabolically active, and releases several hormones and other chemicals and can be thought of as an endocrine organ in itself. These hormones are active in a range of processes including carbohydrate metabolism, lipid metabolism, appetite regulation, body weight stability, immunity, blood clotting and reproduction. Increased visceral fat therefore disrupts the normal balance and function of all these processes.  Ultimately this increases your risk for cardiovascular disease, stroke, diabetes and cancer. 

An individual’s cardiometabolic risk cannot be fully appreciated using BMI alone. Since the same volume of muscle weighs more than fat, some people with  a high muscle mass but low fat percentage will be classed as obese or overweight by BMI but actually have  allow risk for metabolic disease. 

When a doctor or health professional tells their patients that they need to lose weight, what they actually mean is that they need to lose fat. Ideally patients would lose fat and gain muscle, so they may actually gain weight in the process of becoming healthier. Increased muscle mass is associated with decreased risk in cardiovascular disease and a longer life. Using the weighing scales on a daily basis is a common practice which has no bearing on your health. Fluctuations in weight over days has more to do with changes in hydration and bowel movements than fat composition.

Waist measurement is a good measure for abdominal adiposity and is a good predictor for health risk and for diagnosing metabolic syndrome. As a general rule your waist circumference in cm should be less than 50% of your height in cm. The gold standard test for measuring body composition is a DEXA scan. 

The way your body distributes and stores fat has a strong genetic component. However our lifestyle and environmental factors play a key role too, particularly our diet and exercise habits. Consuming excess calories, especially from a diet high in fatty foods and refined carbohydrates, along with an inactive lifestyle are the main causes for build up of visceral fat. 

So what can we do to reduce/ prevent excess visceral fat? 

• Fat is a store of excess energy. Being fat simply means you’ve consumed more energy than you need. Eating a healthy diet, reducing your overall calorie intake is the easiest way to lose fat. Focus on whole, fresh foods including vegetables, fruit, nuts, whole grains and sufficient lean protein. Limit / avoid refined carbohydrates, fatty foods, ultra-processed food, excess salt intake - all these make you want to eat more and cause cravings. 

• Try to exercise on most days. A mixture of both aerobic and resistance training. In addition, keep as physically active as possible - take the stairs when possible, walk or cycle rather than driving.

• Limit alcohol intake.

• Get sufficient sleep. Aim for 7-8 hours of quality sleep per night. Establish a routine and practise good sleep hygiene as lack of sleep may increase your risk of increased visceral fat.

• Learn how to manage your stress response. Find what works for you. Chronic stress increases your cortisol levels which trigger the storage of visceral fat and cravings for food.

 If you would like to test your personal risk factors for developing chronic diseases of ageing, find out more about the Longevity Annual health check and download the longevity doctor guide to healthy living.