Visceral fat – the hidden fat in our body

Alfred Chan, HK BioTek Nutritionist Intern

What is visceral fat Typically, about 90% of our body fat is subcutaneous, this type of stores just beneath our skin. The remaining 10% — called visceral fat, can be found inside the abdominal cavity, and wrap around several vital organs, such as the liver, stomach, pancreas, and intestine. However, if you own a big belly, that’s not necessarily visceral fat only, but maybe is both types of fat. Despite visceral fat only take up a tiny proportion of our body fat, it can actively boost the risk of various health issues. For example, excess abdominal fat can contribute to inflammation and high blood pressure, which is also known as central obesity. Why it is harmful Visceral fat cells are especially “active” in our body by producing various kinds of proteins such as hormones and inflammatory substances rather than just storing as spared energy source when comparing to normal fat cells like subcutaneous fat. One example of these proteins is called cytokines, which can trigger long-lasting inflammation and promote the formation of plaque inside the arteries. Over time, this can serve as a risk factor for heart disease and other chronic diseases. Meanwhile, visceral fat cells take part in building-up a precursor to angiotensin, a protein that constricts blood vessels and soars blood pressure. Besides, it is suggested that visceral fat secretes more retinol-binding protein4 (RBP4) which significantly enhances insulin resistance, meaning that a greater chance of getting type-2 diabetes. Another issue with visceral fat comes to its influence on a ‘fat hormone’ and disrupts the regulation of body fat. As a result, the body creates extra fat than the actual need. Also, according to Harvard research, carrying a high level of visceral fat is strongly associated with several other severe medical conditions. These include:

• Stroke Dementia

• Alzheimer's disease Asthma

• Breast cancer

• Colorectal cancer

How can we know the amount of visceral fat hiding inside our bodies?

You cannot always touch it or observe it. In fact, we may have a pretty flat tummy and still possess certain visceral fat. That is what we called "thin outside, fat inside" (TOFI). Therefore, it is difficult to judge how much visceral fat your body contain accurately without a costly and time-consuming imaging test such as CT or MRI scan. However, an excessively protruding belly and a huge waist are two warning signs that we may carry too much of visceral fat.

Owning a massive waist circumference can be strongly correlated to a high visceral fat content, hence a simple method to determine if you are in danger for relevant health problems is by measuring your waist. We can further access the waist-to-hip ratio (WHR) to forecast the risk of metabolic complications, especially diabetes.

• Measure either in cm or inch

• Waist circumference – the narrowest part of the torso

• Hip circumference – the widest part of the hip

According to WHO, the benchmark for visceral fat or abdominal obesity are as follow:

Risk Factor	Men	Women
Waist circumference	>102 cm / 40 in	>88 cm / 35 in
Waist circumference (Asian)	>90 cm / 35.5 in	>80 cm / 31.5 in
WHR (young adults)	≥0.94	≥0.82
WHR (Older adults)	≥1.03	≥0.90

Besides, the position where our bodies tend to deposit fat can provide us a clue. An “apple shaped” body type – a big belly and slimmer legs – is usually indicates greater level of visceral fat. This shape is more prevalent among men. In contrast, women are more likely to be “pear shaped” with bigger buttocks and thighs. How to get rid of it via diet Apart from maintaining regular exercise and healthy lifestyle, a nutritious and balanced diet is also a key to toss out fat from our body. Try to stay away from certain foods that seem to foster belly fat. One majority of them comes to trans fats which are famous in rising “bad” cholesterol and lowering “good ”cholesterol. Examples includes processed baked goods, refined carbohydrates (e.g. white rice and sodas), deep-fried food and hydrogenated oils (e.g. shortening and margarine). The foods and drinks which contain added sweeteners are with high fructose content which are not good to our health either. Therefore, always consume a bunch of fresh products, whole grains like quinoa and oatmeal, lean protein like skinless chicken, fish, eggs, beans, and low-fat dairy. In addition, a 2012 study from the American Society for Nutrition has demonstrated that a high intake of calcium and vitamin D is beneficial for reducing visceral fat. Hence, don’t be afraid of loading up on leafy greens like kale, spinach and beet, as well as other good sources such as tofu, sardines and dairy foods.

In certain situations, low-carb diets may be an efficient way to cut down visceral fat. Such as the ketogenic diet and the Atkins diet. Indeed, several studies have suggested that low-carb diets are more effective in term of visceral fat reduction than low-fat diets, that most of us generally believe and choose.

Seek professional advice from your doctors or dietitians before making any dietary changes.

References:

• Berber A, Gómez-Santos R, Fanghänel G, Sánchez-Reyes L. Anthropometric indexes in the prediction of type 2 diabetes mellitus, hypertension and dyslipidaemia in a Mexican population. Int J Obes Relat Metab Disord. 2001 Dec;25(12):1794-9. doi: 10.1038/sj.ijo.0801827. PMID: 11781760.

• Harvard Medical School.(2019). Abdominal fat and what to do about it. Retrieved from https://www.health.harvard.edu/staying-healthy/abdominal-fat-and-what-to- do-about-it

• Jung, S. H., Ha, K. H., & Kim, D. J. (2016). Visceral Fat Mass Has Stronger Associations with Diabetes and Prediabetes than Other Anthropometric Obesity Indicators among Korean Adults. Yonsei medical journal, 57(3), 674–680. https://doi.org/10.3349/ymj.2016.57.3.674

• Rosenblum, J. L., Castro, V. M., Moore, C. E., & Kaplan, L. M. (2012). Calcium and vitamin D supplementation is associated with decreased abdominal visceral adipose tissue in overweight and obese adults. The American journal of clinical nutrition, 95(1), 101–108. https://doi.org/10.3945/ajcn.111.019489

• Sasakabe T, Haimoto H, Umegaki H, Wakai K. Association of decrease in carbohydrate intake with reduction in abdominal fat during 3-month moderate low-carbohydrate diet among non-obese Japanese patients with type 2 diabetes. Metabolism. 2015 May;64(5):618-25. doi: 10.1016/j.metabol.2015.01.012. Epub 2015 Jan 29. PMID: 25682064.