Until about ten years ago, brown adipose tissue was considered to be biologically active only in babies and small children, generating heat by burning fat, but there is now no doubt that active brown fat is present in adult humans, involved in cold-induced increases in whole-body calorie expenditure, and thereby, the control of body temperature and how fat we are.

In 2013, researchers showed that one could activate brown adipose tissue by chilling people out long enough: two hours of cold exposure every day for six weeks, which can lead to a significant reduction in body fat. Although they demonstrated the effective recruitment of human brown fat, it would seem difficult to increase exposure to cold in daily life. Thankfully, our brown fat can also be activated by some food ingredients, such as capsaicin, the compound that makes hot peppers hot.

Whereas increased physical activity is usually recommended to increase energy expenditure, specific food components, such as capsaicin, are known to burn off calories and fat.

There was a significant rise in energy expenditure within 30 minutes of eating the equivalent of a jalapeno pepper.

Normally, when we cut down on calories, our metabolism slows down, undercutting our weight loss attempts. But sprinkling a third of a teaspoon of cayenne pepper powder onto our meals counteracts that metabolic slowdown and promotes fat burning. They wanted to try giving them more, to try to match some of the studies done in Asia, but they were working with Caucasians. There is a difference in maximum tolerable dose of red chili pepper between Asians and Caucasians. Take some Japanese women, and you can boost the fat burned after a high-fat meal too, adding over a tablespoon of red pepper powder.

We’ve known for decades that cayenne pepper increases metabolic rate, but we didn’t know how. But now, we have studies showing that this class of compounds increases energy expenditure in human individuals with brown fat, but not those without it, indicating that they increase expenditure straight off the bat. And there’s all sorts of structurally similar flavor molecules in other foods, like black pepper and ginger, which we expect to activate thermogenesis as well, but they haven’t been directly tested.

All these results suggest that the anti-obesity effects of pepper compounds are based on the heat-generating activity of recruited brown fat. Thus, repeated ingestion can mimic the chronic effects of cold exposure without having to freeze ourselves.

Consumption of spicy foods may help us lose weight, but what about the sensory burn and pain on our tongues, and sometimes in our stomach as well as further on down? So, are our only two options for boosting brown fat to freeze our legs or burn our butts?

Arginine-rich foods may also stimulate brown adipose tissue growth and development through a variety of mechanisms, which just means eating more soy foods, seeds, nuts, and beans.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

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