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Flip on Your Fat-Burning Switch

I’ve been telling you for decades that eating fat is not bad for your health. In fact, the opposite is true.

And a large new study of more than 135,000 people proves it. The Prospective Urban Rural Epidemiology (PURE) study looked at the diets of those people over seven years. The findings turn fat phobia on its head. Results showed:

  • High carb — not high fat — diets increased the risk of death by 28%.
  • Higher fat was linked to a 23% lower risk of death.
  • Higher fat was NOT linked to more heart attacks or more deaths from heart disease.
  • Higher saturated fat was linked with a 21% LOWER risk of stroke.1

The truth is that not all body fat is harmful. You see, your body has two types of fat — white and brown.

White fat accumulates under your skin and pads your hips when you take in too many calories. It also builds up around your internal organs to cushion and insulate them. But when too much of this white fat collects around your organs it becomes dangerous “visceral” fat.

But brown fat is much more active than white fat.

Brown fat contains mitochondria — your cellular power plants — that generate heat. This helps regulate your body’s internal temperature when temperatures outside change. In fact, this is the type of fat that babies are born with. It turns up their body heat and helps them survive.

For a long time, researchers assumed ALL of that brown fat disappeared during childhood. But exciting research shows that young children and adults have brown fat, too.

For the first time, this research showed that adults have brown fat.2 And that this brown fat has a critical role in regulating body weight.3

In one study, published in the prestigious New England Journal of Medicine researchers reviewed PET scans and CT scans from 1,972 adults. They found that the more brown fat you have, the more protected you are against obesity.4

Another study, published in the Journal of Clinical Investigation, found that brown fat can burn at least five times more stored energy than other fat.5

And the good news is you can easily produce more brown fat or rev up your existing brown fat to burn more calories.

We now know that white fat can be transformed into tissue that acts like brown fat. It’s called “beige” or “brite” (brown in white) fat.

In 2015, researchers identified this new type of fat in adults. This beige fat exists in pockets within fat tissue. They also found that mice with more beige fat were protected from diabetes and obesity. By burning calories to generate heat, the mice were more easily able to shed excess white fat.6

And one of the easiest ways to do this is to chill out…

In a 2017 study, researchers followed 12 people with lower than average amounts of brown fat. They had them sit in a 63-degree Fahrenheit room for two hours a day for six weeks. After six weeks, they were burning an extra 289 calories in the colder conditions. In addition, tests showed that their beige fat activity had increased.7

In a second study, participants wore a cold suit set to 64.4 degrees Fahrenheit for three hours. They burned an extra 250 calories.

But with our central air and heat set to comfortable warmer temperatures, we aren’t as cold as we used to be for long enough periods of time. Luckily, here at the Sears Institute for Anti-Aging Medicine I’m helping my patients dial up their brown and beige activity for a leaner, trimmer body…

Flip On Your Fat-Burning Switch

Here’s what I recommend to my patients:

  1. Eat more fat. Too little fat or the wrong kinds of fats can reduce your brown fat activity. I help my patients focus on the right kind of fats. Omega-3 fatty acids are essential for brown fat activity.

    Your body can’t make omega-3 fats. You have to get them from food. To get more omega-3s, I advise my patients to eat plenty of wild-caught salmon as well as meat, organ meat and eggs from grass-fed livestock and pastured poultry.

  2. Increase your metabolism with thermogenic foods. Certain foods can activate your brown fat and increase your metabolism. These “thermogenic” foods include green tea, ginger and aged garlic and apples (skin on). But perhaps the most effective brown fat-burning food are hot peppers.

    Capsaicin is a compound that makes hot peppers hot. It is known to burn off calories and fat. Capsaicin can raise your energy expenditure in just minutes of eating one jalapeño pepper.

  3. Boost your melatonin levels. You know melatonin as the sleep hormone, but it also activates brown fat…

    A study in the Journal of Pineal Research found that rats who had more melatonin also had more activated brown fat.8 And they burned more calories. Tropical fruits are a great way to increase melatonin. Pineapples have been shown to increase blood levels by 266%. Bananas boost it by 180% and oranges by 47%.9

    If you supplement, I suggest taking 3 mg a day 20 minutes before bedtime. But take the right kind… When you take melatonin by mouth, it breaks down in the liver. Most of it never gets to the bloodstream. Instead look for sprays, drops or a sublingual tablet. They’re easier to absorb and work faster.

To Your Good Health,
Al Sears, MD
Al Sears, MD, CNS


1. Dehghan M, et al. “Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study.”The Lancet .20174;390(10107):2050-2062.
2. Saito M, et al. “High incidence of metabolically active brown adipose tissue in healthy adult humans: effects of cold exposure and adiposity.” Diabetes. 2009;58(7): 1526-1531.
3. Moyer Wenner M. “Supercharging Brown Fat to Battle Obesity.” Scientific American. July 15, 2014.
4. Cypess AM, et al. “Identification and importance of brown adipose tissue in adult humans.” N Engl J Med. 2009;360(15):1509-1517.
5. Cannon B, and Nedergaard J. “Yes, even human brown fat is on fire!” J Clin Invest. 20121; 122(2): 486–489.
6. Ikeda K, et al. “UCP1-independent signaling involving SERCA2bmediated calcium cycling regulates beige fat thermogenesis and systemic glucose homeostasis.” Nat Med. 2017;23(12):1454-1465.
7. Yoneshiro T, et al. “Recruited brown adipose tissue as an antiobesity agent in humans.” J Clin Invest. 2013;123(8):3404-3408.
8. Jiménez-Aranda A, et al. “Melatonin induces browning of inguinal white adipose tissue in Zucker diabetic fatty rats.” J Pineal Res. 2013;55(4):416-423.
9. Johns NP, et al. “Dietary intake of melatonin from tropical fruit altered urinary excretion of 6-sulfatoxymelatonin in healthy volunteers.” J Agric Food Chem. 2013;61(4):913-919.