Research Proven Weight Loss: Spicy Foods


Spicy Food Are Key to Lasting Weight Loss

It has long been postulated that spicy foods can help to speed up your metabolism.  Capsaicin, which is the active ingredient in hot peppers, makes you sweat like you just exercised, but does it affect your metabolism?  Do chilies raise your body temperature and require your body to “turn the air conditioner” on to keep you cool?  The information on how, if,  and how long has been varied and remains unclear.   

Red hot Chile pepper
Red hot Chile pepper

What Is Metabolism?

Metabolism is the complex of physical and chemical processes occurring within our bodies that are necessary for the maintenance of life.  In metabolism, some substances are broken down to yield energy, such as alcohol, carbohydrates, fats, and proteins, for vital processes, such as cooling your body and are necessary for life.  Simply put, metabolism is the amount of energy or calories needed by our bodies to maintain themselves.  Each of our metabolisms is affected by our body composition.  People with more muscles will have a higher metabolism, while those that are less muscle have a lower metabolism.

If you have a higher metabolism, you will be able to eat more calories daily without gaining weight than someone with a lower metabolism.  Though there are several ways that are said to increase metabolism, the most well-documented means to increase your metabolism is by adding muscle mass through resistance or strength training exercises.  

Can hot peppers also increase your metabolism?  Thermogenesis is the process in our metabolism in which our bodies produce heat.  Many supplements work by producing this effect.  This word is the term which I will use to discuss if capsaicin increases the metabolism or heat within the body and requires us to expend energy to lower this temperature.  

Multiple Peppers
Multiple Peppers

Other Effects of Capsaicin

I know we are here to discuss the metabolism effect of capsaicin, but what other effects does it have?  Capsaicin is the source from which hot peppers get their heat. It is found in jalapenos, habaneros, cayenne, serranos, and most other chili peppers as a colorless compound.  Along with its thermogenic effect, capsaicin is shown to work as an anti-inflammatory[1] and blood thinner by helping to prevent blood clots[2].  So, not only might they increase weight loss, but they also might help decrease clots and your knee pain.  The anti-inflammatory and blood thinning effect could be a double whammy to help prevent heart disease.

Red peppers
Red hot peppers on the table

Does Capsaicin Increase Metabolic Rate?

It is postulated that capsaicin increases your metabolic rate by increasing thermogenesis and requiring you to expend energy to cool the body.  I would say that this claim misses part of the mechanism.  I would say that spicy foods also decrease calorie intake because the hotter foods tend to slow eating.  Although this mechanism was difficult to prove, below is some research to show that hot peppers and capsaicin can help you reduce your weight.  

Scoville pepper heat scale
Scoville Units: pepper heat scale
Warning! Please Take Caution Eating Hot Peppers.
When you bite into a hot pepper, you may feel discomfort. The hotter the pepper, the more burn you will feel in your mouth.  Casein in milk or eating cool cottage cheese may reduce the discomfort. Start with a pepper low in Scoville units and work your way up in strength. 

Research on Capsaicin:  

  1. One study looked at the thin and obese female who were given a diet that contained capsaicin, and they found that capsaicin increased the thermogenesis of both obese and lean women more than the control group​[3]​.  The study looked at capsaicin consumption and fat accumulation over eight days and found that fat deposits decreased by 62% over that period.  The effect was modest but significant, and even though it would take a larger effect to cause dramatic effect, over a lifetime, the impact could be considerable.
  2. Other studies looked at men given 6-10 grams of red pepper in their meals.  The first study looked at carbohydrate oxidation (burning) after meals containing 10 grams of red pepper.  They found that the group that ate the red pepper had high oxidation of carbohydrates for 150 minutes after the meal was consumed​[4]​.  It was postulated that this is due to beta-adrenergic stimulation, yet another mechanism that might increase energy burned after eating capsaicin.  An additional study of red pepper looked at red pepper and appetite and found that men who ate the red pepper at the maximum tolerable dose of 6-10 grams also reduced their total food calorie intake​[5]​.  Last, they found that red pepper diets also reduced total fat intake​[6]​.  
  3. A study looked at thermogenesis and beta-adrenergic receptors.  The study found that adrenergic action of capsaicin resulted in a decrease in the adipose (fat) tissue weight and serum triglyceride concentration in rats fed a high-fat diet supplemented with capsaicin​[7]​.  This effect should translate to weight loss or at least maintenance in humans since our fat cells and adrenergic receptors are similar.  This thermogenic effect was confirmed by another study​[8]​.
  4. Lastly, one study looked at blood glucose and insulin production after ingestion of 5 grams of capsaicin and found that capsaicin appears to increase blood insulin and reduce blood glucose​[9]​.  
Assorted Hot Chili Peppers
Assorted Hot Chili Peppers

Final Recommendations on Hot Peppers:

  1. Hot peppers appear to reduce both total fat intake and calorie intake.  This could help you reduce your belly fat over time, and although the effect is not huge, it certainly could have a lasting effect on both maintaining weight and reducing it.
  2. Hot peppers appear to decrease appetite.  This is self-explanatory but decreased eating clearly will help weight loss.  
  3. Hot peppers increase thermogenesis.  This will increase the calories you burn.  Do not expect an extra pound lost per week, but you might see a pound or two less gained per year.
Man Eating Spicy Food
A Man Eating Spicy Food
  1. Hot peppers have an anti-inflammatory effect.  They may decrease your knee pain or reduce your risk of heart disease if you eat them regularly and not covered with cheese.  Talk to your medical provider if you are on aspirin therapy or other blood thinners because capsaicin might increase their effects.  
  2. Hot Peppers assist with glucose maintenance.  Hot peppers may decrease glucose and raise insulin.  Talk to your medical provider if you are diabetic because capsaicin might assist with lowering your blood glucose.  
Warning! Please Take Caution Eating Hot Peppers.
When you bite into a hot pepper, you may feel discomfort. The hotter the pepper, the more burn you will feel in your mouth.  Casein in milk or eating cool cottage cheese may reduce the discomfort. Start with a pepper low in Scoville units and work your way up in strength. 

The bottom line: You can clearly see that hot peppers and spicy foods are a healthy addition to your diet and will likely assist in weight maintenance and loss.  I recommend it, but too much can cause problems.  Start slow and raise your hot pepper consumption slowly.  I recommend fresh peppers or spices, but pill form may be ok if you can’t tolerate the real thing.  


  1. [1]
    C. Kim et al., “Capsaicin exhibits anti-inflammatory property by inhibiting IkB-a degradation in LPS-stimulated peritoneal macrophages.,” Cell Signal, vol. 15, no. 3, pp. 299–306, Mar. 2003. [PubMed]
  2. [2]
    J. Wang, M. Hsu, T. Hsu, and C. Teng, “Antihemostatic and antithrombotic effects of capsaicin in comparison with aspirin and indomethacin.,” Thromb Res, vol. 37, no. 6, pp. 669–79, Mar. 1985. [PubMed]
  3. [3]
    T. Matsumoto, C. Miyawaki, H. Ue, T. Yuasa, A. Miyatsuji, and T. Moritani, “Effects of capsaicin-containing yellow curry sauce on sympathetic nervous system activity and diet-induced thermogenesis in lean and obese young women.,” J Nutr Sci Vitaminol (Tokyo), vol. 46, no. 6, pp. 309–15, Dec. 2000. [PubMed]
  4. [4]
    M. Yoshioka et al., “Effects of red-pepper diet on the energy metabolism in men.,” J Nutr Sci Vitaminol (Tokyo), vol. 41, no. 6, pp. 647–56, Dec. 1995. [PubMed]
  5. [5]
    M. Yoshioka et al., “Effects of red pepper on appetite and energy intake.,” Br J Nutr, vol. 82, no. 2, pp. 115–23, Aug. 1999. [PubMed]
  6. [6]
    M. Yoshioka et al., “Maximum tolerable dose of red pepper decreases fat intake independently of spicy sensation in the mouth.,” Br J Nutr, vol. 91, no. 6, pp. 991–5, Jun. 2004. [PubMed]
  7. [7]
    T. Kawada, T. Watanabe, T. Takaishi, T. Tanaka, and K. Iwai, “Capsaicin-induced beta-adrenergic action on energy metabolism in rats: influence of capsaicin on oxygen consumption, the respiratory quotient, and substrate utilization.,” Proc Soc Exp Biol Med, vol. 183, no. 2, pp. 250–6, Nov. 1986. [PubMed]
  8. [8]
    R. Hursel and M. Westerterp-Plantenga, “Thermogenic ingredients and body weight regulation.,” Int J Obes (Lond), vol. 34, no. 4, pp. 659–69, Apr. 2010. [PubMed]
  9. [9]
    K. Chaiyasit, W. Khovidhunkit, and S. Wittayalertpanya, “Pharmacokinetic and the effect of capsaicin in Capsicum frutescens on decreasing plasma glucose level.,” J Med Assoc Thai, vol. 92, no. 1, pp. 108–13, Jan. 2009. [PubMed]
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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