A middle-aged bank employee, who is overweight by more than 30 percent and has diabetes and hypertension, came to consult us for chest pains. On work-up, he showed signs of premature clogging of his heart arteries. It was not so bad yet, but needed to be addressed urgently.

“I’m careful with my diet and I hardly eat any sweets. Why do I remain overweight?” he asked almost in protest.

We inquired about his lifestyle, including his level of physical activity and asked if he has any form of exercise. He replied that although he’s a member of a popular gym with complete facilities, he’s too busy and can’t find the time for exercise. Well, that is most likely the culprit. Excessive stress with lack of physical activity makes for a perfect brew of various health problems.

Why do people who exercise regularly find it easier to lose weight? Why do they have better chances of remaining healthy, with a much lower risk of diabetes, hypertension, cholesterol and other cardiometabolic problems?

It’s likely due to the type of fat cells they’re able to predominantly develop.

Two types

We have two types of adipose tissues or fat cells—white or brown fats. White fat is energy or calorie-storing, while brown fat is energy-burning. So, if you have more white fat, you tend to put on weight though you may not eat excessively, while if you have enough brown fat, you tend to burn the calories more efficiently and you’re able to maintain your ideal body weight. Excess white fat could lead to obesity, diabetes and other cardiometabolic problems.

Why do the two types of fat cells impact our metabolism differently? Scientists tell us that it may be due to the number of mitochondria, which are the parts (organelles) of the cells responsible for converting the calories we take into actual energy (adenosine triphosphate or ATP) which could be used by the different organs of the body. ATP is the currency used by all cells of the body to function normally.

The mitochondria have been described as the “powerhouse” which contains the “engines” that burn calories to produce heat. White fat has much fewer mitochondria and more fat droplets, compared to brown fat, which is densely-packed with mitochondria. Hence, brown fat is able to produce heat much more efficiently than white fat.

Brown fat also plays an important role in regulating the body’s core temperature since it continually burns stored calories as fuel. To some degree, white fat may also help regulate core temperature by insulating organs, but it’s not as efficient as brown fat since it (white fat) does not burn calories and generate heat well enough.

We first heard of the importance of having enough brown fat in the body from Dr. Augusto Litonjua several years ago. Dr. Litonjua, who pioneered the medical subspecialty of Endocrinology in the country, remains an active, much-respected icon in the field of Endocrinology in Asia and the rest of the world. He’s probably in his early 90s now but he still attends to patients, although mostly by teleconsultation since the start of the pandemic. But we hear he still gives occasional lectures in medical conventions and lay forums to educate everyone on how to prevent and control diabetes, obesity and their various complications like heart attack, stroke, blindness and leg amputations.

‘Good fat’

In one of the symposia we lectured in together, Dr. Litonjua said that exercising properly is key to develop one’s brown fat. He called it the “good fat,” while white fat is the “bad fat”. He stressed that exercising at the right temperature can help reduce white fat and promote the good brown fat.

Dr. Litonjua does not encourage exercising at room temperature or in a slightly cool, but not cold-enough rooms. He cited studies showing that brown fats are activated during exercise when the room temperature is around 63° to 66° Fahrenheit. This is equivalent to 17° to 19° centigrade. He advises his patients to wear light clothes during exercise, turn down the thermostat of the aircon and even supplement it with electric fans.

We thought this might cause some chilling, which is generally not good. But when we tried it and surprisingly, we felt comfortable. We generate heat as we exercise and doing so in a cold room provides just the right room temperature, in combination with the elevated body temperature we generate with exercise.

In a published Swedish study, researchers—aside from maintaining the room temperature of 63°F to 66°F—also made their subjects immerse one foot in ice water for 5 minutes at a time, followed by five minutes out of the water. The study showed a significantly higher amount of brown fat as shown by scanning after the study and that the added exposure to the cold ice water boosted their brown-fat activity 15-fold. The researchers hypothesized that the exposure to lower temperatures increased the activity of a gene in the body that converts white fat to brown.

According to Dr. Litonjua, white fat makes up the bulk of the fat in our bodies. All the excess calories we consume, especially due to overeating, are stored in the white fat. Consequently, overweight and obese people have more white fat than normal-weight individuals.

Brown fat, usually present in small pockets in the body, is the more ideal of the two types of fat because it burns calories much more efficiently, producing heat under the right conditions. Studies show that the fully activated brown fat generates 300 times more heat than any other tissue in the body.

Glucose control

By itself, brown fat can burn several hundred calories per day and a mere two ounces of brown fat burns the equivalent of 30 minutes of moderate intensity exercise. Our small pockets of brown fat are usually located in the sides of the neck—sometimes up to the shoulder and upper arms and just above the collarbone. Some worry if they have prominent fatty tissues in these areas and even ask the cosmetic surgeons to take them off. They should be grateful for these pockets of brown fat.

Brown fat may also be found on the upper back between the shoulder blades and along the sides of the upper spine. The amount is actually so small and lie deep under the skin, so they don’t appear as bulges. Belly fat is definitely not brown fat; it’s likely white visceral fat, which is the exact opposite of brown fat. It can secrete bad hormones that can cause heart attacks and other cardiovascular problems.

The benefits of brown fat are well documented in diabetics. Lower blood sugar or glucose levels have been linked with a bigger amount of brown fat. The researchers conclude that brown fat may play a direct role in glucose control.

In a study at Joslin Diabetes Center involving experimental mice, the research team transplanted a small amount of brown fat from one group of mice into the abdomens of another group. After only eight weeks, the mice with the transplanted brown fat became leaner in weight than those in the placebo group (no transplanted brown fat) and their blood sugar levels were more normal.

Aside from regularly exercising at a room temperature of 17° to 19° Centigrade, how else can we increase our brown fat and enhance its activity? Researchers at the University of Iowa isolated a substance in apple peels, which they called ursolic acid and this has been shown also to boost brown fat even in experimental animals given a high-fat diet.

Turning the thermostat of our airconditioners lower may cost us a bit more in electricity bills, but if they can reduce our medical bills due to diabetes or obesity-related diseases, we may be saving much more in the long run. Well, this is probably the real meaning of the colloquial term “chillax”—chill, exercise and relax!