We all have body fat distributed throughout our bodies. Adipose tissue is found beneath the skin and around the internal organs of our bodies. Just like the fats found in our food, some types of body fat are better while others can have a detrimental effect on our health.
Body fat functions as an insulator against extreme temperatures as a reliable energy source. It also forms cell membranes and creates compounds such as vitamin D, hormones, and bile. It is also crucial in the absorption and storage of some key nutrients. However, having too much or too little body fat can cause significant health issues.
Several types of body fat:
- Found when you pinch love handles or squeeze your belly fat
- Located just under the skin and makes up nearly 80% of all body fat
- Considered less harmful than other types of deeper fat
- Secretes leptin or the “obesity hormone” or “fat hormone”
Leptin helps inhibit hunger as well as regulate energy balance. If the person has excess subcutaneous fat, leptin levels increase and over time, cause resistance to the hormone. The more the person eats, the more the fat cells produce leptin.
- Surrounds your internal organs inside the abdominal cavity
- Excess visceral fat can be detrimental to your health
- Secretes large quantities of the pro-inflammatory cytokine interleukin 6 (IL-6)
IL-6 is implicated in a whole list of chronic diseases including diabetes mellitus, with researchers believing the pro-inflammatory cytokine to be the leading cause of insulin resistance. The presence of visceral fat also increases the risk of developing heart disease, stroke, and dementia.
- The fat inside the liver
- Obesity and aging increase intrahepatic fat accumulation that leads to non-alcoholic fatty liver disease and metabolic complications including insulin resistance, diabetes, and coronary heart disease.
- The visceral fat deposits surrounding your heart.
- It can potentially cause inflammation and has a direct effect on heart function and coronary atherosclerosis
- Associated with serious health problems including obesity, diabetes, hypertension, and coronary artery disease
- Distributed around your hips, thighs, and bottom, and is typical of a pear-shaped body type
- May be protective against heart disease and diabetes.
- This type of fat accumulates over time and is much harder to break down than the fat deposits in your upper body
- less detrimental to your health because of fewer pro-inflammatory cytokines released
- Fat deposits are those between and within the muscles, found beneath the muscle fascia
- It’s a good predictor of decreased muscle function and mobility, particularly in older adults
- Implicated in a variety of conditions including stroke, insulin resistance, and diabetes
- Injury to the muscles, obesity, age, inactivity, and disease are all factors that increase the levels of intermuscular fat.
- Intramuscular fat is found within the muscle and occurs during aging and in some pathological circumstances.
- It serves as an energy store for the body, that can be used during exercise. Higher levels of intramuscular fat have been associated with abnormal blood pressure, lipids, and glucose levels, mainly due to the levels of body fatness overall.
- However, higher levels of intramuscular fat alone are associated with the presence of metabolic syndrome.
- Brown fat is considered more like muscle than fat because when activated, it burns fat.
- Recent studies have found that lean people have higher levels of brown fat than those who are overweight or obese. Children also have more brown fat to help protect them from the cold. In adults, the brown fat is more active in the colder months to assist with temperature regulation.
Fat is distributed differently between genders and populations.
Your gender can greatly depict where you’re more likely to carry excess body fat as well as the diseases you’re at risk of getting. Upper-body fat is more common in men, which increases their risk of heart disease, stroke, diabetes, hypertension, and even cancers. Women, on the other hand, are more likely to carry their fat in the lower body which is generally not associated with chronic diseases. Women, post-menopause, often begin to store the fat around their waist and abdomen due to a reduction in estrogen, though it’ll be to a lesser extent compared to men.
Fat is also distributed around the body in different populations. Japanese men, for example, carry more body fat for a given BMI than white Australians. Australian Aboriginal women have a greater waist circumference when compared to Australians of European descent. South Asian people have smaller subcutaneous fat reserves with greater risk of visceral fat gain than white people. And black Americans carry more subcutaneous fat and less visceral fat than white Americans.
The harmful effects of inflammation and fat tissue Chronic inflammation contributes to a whole host of chronic diseases. Inflammation of fat tissue is implicated in the development of metabolic syndrome problems, including type 2 diabetes.
Adipose tissue secretes proteins, known as adipokines, that help regulate your energy balance as well as other body functions. In the event that adipose tissue is allowed to accumulate, especially around the abdomen, genes are activated, creating adipokines involved in inflammation and insulin resistance. Elevated blood lipids due to a high-fat diet or obesity also promote inflammation.
Inflammation is also driven by an increase in the number of immune cells located in the adipose tissue. Scientists have found that high-calorie diets cause fat cells to make a group of proteins called major histocompatibility complex II (MHCII). These proteins are usually activated to support the immune system in fighting off pathogenic viruses and bacteria. In overweight people, adipocytes generate false distress signals, which activate the immune cells and cause inflammation.
The occurrences of this inflammation start with an excess of nutrients entering the bloodstream. These are converted and stored as fat and stimulate the secretion of leptin. As the person continues to consume a high-calorie diet, leptin levels increase and cause nearby CD4 T cells to become excited. This eventually leads to the proteins producing MHCII, resulting in inflammation. Essentially this is an uncontrolled immune response to the modern-day, high-calorie diet and is likely to have severe long-term consequences for people who are overweight or obese.
All these factors explain why chronic inflammation is associated with obesity and how an excess of adipose tissue contributes to metabolic syndrome and leads to chronic diseases. As you would expect, weight loss will see a reduction in the number of immune cells located in the adipose tissue, which will lead to hormone regulation and so, alter the gene expression, resulting in an improved inflammatory status long term.