What is the Thermic Effect of Food?

“What is the Thermic Effect of Food” was written by Jenny Ingolia and reviewed/edited by Kasey Hageman MS, RD, LD. Jenny is a graduate dietetic student at Clemson University.

Weight loss can seem impossible for most people. Although it isn’t an easy thing to take on, it doesn’t have to be as complicated as you may think.

Weight loss can be summed up into two words: calorie deficit. A caloric deficit occurs when you are eating fewer calories than your body needs. Basal metabolic rate or BMR is the amount of calories your body needs at rest to function throughout each day. A caloric deficit can be achieved by eating fewer calories from food, burning calories from exercise, or a mixture of both.

However, there are also other ways your body burns calories naturally. These include non-exercise activity thermogenesis or NEAT, and the thermic effect of food or TEF. These other factors also contribute to your total daily energy expenditure or TDEE.

“Wait, so are you saying I don’t have to eat less or exercise and I can still lose weight?” Not exactly.

TDEE includes four main components:

  1. BMR
  2. NEAT
  3. TEF
  4. EAT (exercise activity thermogenesis)

As you can see from the image below, your BMR is responsible for most of your energy expenditure. BMR accounts for about 70% whereas NEAT is responsible for 15%, TEF 10%, and EAT 5%. 

Let’s focus on that TEF category. Calories burned while eating creates the thermic effect of food. The thermic effect of food increases from digestion and heat production. When you eat food, your body works to digest it and absorb its nutrients. This in turn creates heat and burns calories.

However, the amount of calories burned is relatively negligible in the grand scheme of weight loss. Let’s start by discussing foods that considered thermogenic. We will look at what the science says and how these foods can be beneficial for weight loss outside of their potential thermogenic effect.

Thermogenic foods

Green tea & coffee

Caffeine-containing beverages like coffee and green tea are commonly thought to be thermogenic. The theory behind this is that the caffeine and polyphenols (read: organic compounds in tea and coffee) in these drinks act on hormones and our sympathetic nervous system. This increases our metabolic rate and fat burning.

The science isn’t definitive on this so should you be drinking a bunch of coffee and tea every day? No. Even if it were true, the TEF equates to only about 10% of your TDEE and proteins, not liquids, are known to have the highest TEF.

However, tea and coffee can be a part of your weight loss journey. Both naturally low in calories, coffee and tea can go well with a meal and even provide you with a boost of energy. Recent studies have even shown that coffee may increase fat-burning during exercise when drunk 30 minutes before the activity. 

In conclusion, drinking a lot of coffee and tea every day will not inherently make you lose weight. However, with other interventions they can be a part of a comprehensive weight loss plan.

Spices

Various spices are thought to be thermogenic including turmeric, black pepper, and cinnamon. Turmeric contains a compound called curcumin, which is believed to interact with fat cells. Many people believe that it can reverse insulin resistance and hyperlipidemia, known obesity-inducing factors. A similar thermic effect of food has been studied in black pepper, chili peppers, cinnamon, and ginger. 

Unfortunately, these studies and reviews have not had conclusive results so no official recommendations have been set. So before you start putting turmeric on everything because you think it is going to help you lose weight, let’s talk about some proven benefits of turmeric that may play a great role in your healthy lifestyle.

  • Antioxidant and anti-inflammatory: may help with muscle soreness and reduce damaging compounds in your body known as free radicals
  • Offers a unique flavor in recipes like curries and teas
  • When paired with black pepper, absorption increases by 2000%

Spices like turmeric and cinnamon make food taste great with just about 0 calories. Enjoy them for what they are: yummy spices!

Coconut oil

Within the last few years, coconut oil has been somewhat of a buzzword. Its increased use in cooking and baking has allowed people to think it’s a healthy oil alternative. However, coconut oil is a saturated fat. Saturated fats may raise cholesterol levels and increase the risk of heart disease. 

Some consider coconut oil to be thermogenic because it is primarily made of medium-chain triglycerides or MCTs. This is chain length is referring to the structure of the fat.

In the past, researchers believed that the body uses MCTs immediately. That supposedly increases the body’s metabolism and burs more calories. However, current studies have not proven coconut oil’s thermogenic effect and more research needs to be done. Coconut oil is often used in baked goods and other recipes. The current recommendation for coconut oil is to consume it in moderation since it is saturated fat.

*For more on fats, see the blog post Including Healthy Fat Foods in Your Diet.

Chili peppers

Chili peppers contain capsaicin, which is the compound that makes the pepper spicy. Supposedly when eaten, capsaicin increases body temperature, therefore burning calories. For this reason, people think chili peppers are a thermogenic food.

Eating a hot pepper → increased body temperature → heat is created → calories burned. Makes sense right? It’s a little more complicated than that. 

Although there are reviews and studies that have shown positive effects on weight loss and energy expenditure from capsaicin, there have not been enough studies to create conclusive results and official recommendations. 

Some studies mention that the amount of capsaicin someone need have to eat to see these potential benefits is unrealistic. There could also be negative side effects like stomach upset and diarrhea from eating large amounts of hot pepper. 

The question then is, is it worth it to put hot pepper on everything you eat in order to increase your weight loss efforts? No. 

However, use hot pepper for what it is: a great flavor enhancer (if spice is your thing).

Vegetables

Many people consider certain vegetables to be “thermogenic.’ Some of these vegetables include bean sprouts, sweet potatoes, celery, green vegetables, avocado, and garlic. Although the theories vary, it is possible that fiber and other nutrients in these foods helps boost your metabolism. This increased metabolism may burn more calories while you’re eating them. 

As with the other foods discussed here, the research proving their thermogenic effect is essentially non-existent. However, this doesn’t mean vegetables don’t play an extremely useful role in weight management because they actually do. Vegetables are low in calories and filling due to their fiber content. 

Consuming adequate amounts of vegetables (at least half your plate) will help you to stay fuller longer. In addition it will also provide a multitude of necessary vitamins and minerals. 

Does eating vegetables increase fat burning? Probably not and definitely not enough to solely rely on for weight management. 

Does eating vegetables provide your body with nutrients and help balance your meals and hunger throughout the day resulting in sustainable weight loss over time? Absolutely.

Moral of the story: Thermic Effect of Food

Thermogenesis is the production of heat in our body. We know that about 10% of our TDEE comes from the thermic effect food. For example, eating food creates heat which in turn uses calories. 

However, this 10% effect is relatively negligible in a weight loss journey. Proper interventions like a caloric deficit, balanced meals, and physical activity are necessary to create sustainable weight loss. This doesn’t mean you can’t drink green tea or hot peppers. However, try not to think of them as avenues for weight loss. 

When you’re in a caloric deficit, you are likely to be consuming roughly 15-25% less than your TDEE. This number is based on a 2000 calorie diet which already takes into consideration TEF. 

So instead of thinking “How can this food/drink make me lose weight?” think instead about how it tastes and how it makes you feel. The overall calories are what will help lose the weight, not the food itself. 

It is easy to believe false marketing when it comes to weight loss miracles. However, if there were specific foods that could make us all attain a healthy weight, we would all be eating the same things. Unfortunately, that’s too good to be true. 

Weight loss requires personalization and needs to focus on sustainability for life. That sounds a lot better than dumping cinnamon on everything or eating spoonfuls of coconut oil.

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