Updated: Oct 23, 2021
My love of peppers is pretty evident, I have a serving at almost every meal, in the form of a sauce or just plain raw. The effects of capsaicin and weight loss have been widely studied. I knew I wanted to explore it further and wanted to share what I learned.
Researchers in England studied the effects of the combination of MCT oil and Capsaicin (in the form of chili pepper) in Chili on Diet-Induced Thermogenesis (DIT) and level of satiety. Diet-Induced Thermogenesis is when certain foods raise your normal metabolic rate, in order, for your body to process, break down, and store the food product. It's the amount of energy expended to ingest the food.
The study had seven healthy volunteers. They were fed a breakfast containing three combinations of an oil (MCT or Sunflower) and a capsaicin source (chili or bell pepper) on four different occasions, following an overnight fast. Presumably, first thing in the morning, as their first meal. They also measured gastrointestinal discomfort and satiety through a visual analog scale, such as a pain scale or numerical scale. The test subjects were asked to record their dietary intake the previous night before and to duplicate the same meal on each occasion as a control. The subjects were also asked to not engage in any physical activity (like a workout) the evening before as it would affect the basal metabolic rate of their fast as they slept and skew the results for the following morning.
The three breakfast combinations include:
1.) Chili (capsaicin) and MCT oil
2.) Chili (capsaicin) and sunflower oil
3.) Bell pepper and sunflower oil or Bell pepper and MCT oil
What they found was that there were significant changes in thermogenesis thus fat oxidation for all the diets. The researchers found that there was little to no difference between gastrointestinal discomfort and satiety. However, they did find that the addition of chili (capsaicin) and MCT oil raised thermogenesis rates by 50%.
They concluded that accumulated use of both would result in inducing weight loss or maintaining weight loss over time. Before this study was conducted many of the studies on DIT were conducted individually with green tea, or a combination of red pepper and caffeine but none on the combination of MCT oil and red pepper on increased thermogenesis and satiety. It is possible that satiety was satisfied by MCT supplementation due to fat's high caloric density. But red pepper (chili) is what increases thermogenesis. The combination of the two is significant enough to satisfy the two major issues for many of those on a weight loss journey, that is staying full and burning fat while dieting down. If we want to go further, raising metabolic rate while in a fasted or even calorie deficit without actually engaging in physical activity.
In addition, the researchers discovered that fat oxidation increased initially postprandial with "both chili– MCT oil and pepper–MCT oil but not the pepper–sunflower oil or chili–sunflower oil where it decreased for the first hour postprandial and then began to increase gradually thereafter" (Clegg et al., 2012, 1582).
However, we can't ignore that it was a very small sample size, a factor to consider. The findings from this study were very intriguing, especially addressing, how to combat obesity by manipulating or increasing energy expenditure (metabolic rate) to prevent excess storage of fat in adipose tissue (belly fat) through diet alone.
Paleo has taught me that meals should be individualized, and they don't have to look a certain way.
This is still a big deal when many people still eat bread, pastries, or oatmeal and fruit for breakfast. There is nothing wrong with these options, especially for increased fiber and fullness. However, the exploration of quality fat, especially for satiety is worth a second look. In this case, the addition of SPICE in the form of red pepper or bell pepper with that fat can be rather impactful for weight loss, but specifically fat loss.
The findings of this study were compelling about the food synergy of fat (MCT) + capsaicin (Pepper/Spice source) in increasing thermogenesis through diet alone. The possible impact on weight loss and maintaining a weight loss is intriguing. In the future, we will discuss what other types of food products elicit a thermogenic effect.
 Clegg et al. (2012). Combined medium-chain triglyceride and chili feeding increases diet-induced thermogenesis in normal- weight humans. Springer-Ver., 52:1579–1585.