Thermic Effect of Food: Eat to Burn Calories

But first, calorie basics

Calories are energy fuel that we get from foods and drinks that we consume. We get them from the macronutrients: carbohydrates, fat, and protein. We use calories for essential body functions that keep us alive and thriving. This daily calorie goal requirement consists of our:

• Basal metabolic rate: the number of calories we burn at rest. These are needed to perform basic functions such as breathing and circulation. This makes up the bulk of our daily calorie burn. 
  
  
• Activity level: the amount of energy you use to move during the day. This includes activities such as housework, walking, or fitness. 

• Food processing (thermogenesis): digestion, absorption, moving, and storing foods and nutrients you eat (1). 

An important part of a healthy lifestyle is balancing the amount of calories you consume with the calories you burn. In general, if you need to lose weight, you want a calorie deficit, or taking less calories than you burn. If you need to gain weight, the focus shifts to taking in more calories than you burn. 

Thermic effect of food

The thermic effect of food (TEF) is the amount of energy required to digest and absorb the food we eat. Meaning, that we do burn some calories by eating! 

Currently, there’s no way of knowing the exact calorie burn at any given meal but research suggests that certain foods have a higher thermic effect, or burn more calories (2). This number may vary depending on your specific body and the type of bacteria that reside in your gut (3). 

Low burn: more calories absorbed 

Processed 

We absorb more calories from highly processed foods, especially carbohydrates and fats, because they’re easier to break down. We also absorb more calories when a food is cooked, chopped, or blended. For instance, when we eat peanut butter versus having whole peanuts, we absorb almost 38% more fat (4).  

In scientific studies, people who ate a diet full of highly processed foods, consumed more calories and gained more weight when compared to people eating a minimally processed diet (5). Highly processed foods include fast foods, microwave meals, crackers, cakes, sugary beverages, and candy (6). 

High burn: less calories consumed 

Fiber

We absorb less calories from minimally processed foods with more fiber. Picture yourself eating an apple versus drinking apple juice. Eating a fresh apple requires biting, chewing, and more digestive effort to break down the fruit’s cell walls in order to get to the juice. When you drink a cup of apple juice, the calories are absorbed very easily and quickly. In one study, walnuts were shown to be about 20% less calories than predicted. This is because standard food calorie testing methods don’t take into account portions of high fiber foods that don’t get absorbed by our bodies (7). 

Protein 

When eating a diet of protein, carbohydrate and fat, it equates to about 5 to 15% of daily calorie expenditure. These values are higher when it comes to increased amounts of protein in the diet. Protein also helps have an increased effect on satiety (8), meaning it can help us feel more full.

A high-protein meal compared to a high-fat or high-carbohydrate meal, has been associated with an 17% increase in thermic effect. However, it's important the note that these changes may be just during a meal and not necessarily produce long-term changes to our metabolism (9). 

Certain fats: medium chain triglycerides 

Medium-chain triglycerides (MCTs) have gained popularity from the keto diet. MCTs have been suggested to aid in weight loss by stimulating hormones responsible for fat metabolism and blood sugar regulation. Some limited studies have suggested that metabolism was slightly higher after eating an MCT meal when compared to a long-chain triglyceride meal, however it's still important to remember that fat still contributes calories (10). MCTs are found in foods such as butter and coconut oil. 

Caffeine and some spices 

Caffeine is a central nervous system (brain and spinal cord) stimulant found in coffee, tea, cocoa, and added to some soft drinks. Caffeine can increase the metabolic rate by up to about 10% (11). Like any drug, we develop a tolerance to caffeine. So say you’re a regular coffee drinker, the calorie burn won’t have as much as an impact (12). Keep in mind that this calorie burn can be easily offset by sugar in sodas or extras, such as milk or sugar, added to your coffee or tea. 

Some herbs and spices can also slightly increase resting metabolic rate. For instance, hot peppers contain a component that causes a small thermogenic effect of about 50 calories per day (13). Turmeric has been suggested to increase adiponectin, a hormone that balances metabolism (14). Although as spices and herbs usually are consumed in very small quantities, it rarely makes that large of a difference.

You Should Be Adding This Spice to Your Coffee (or Milk!)

Negative calories, not so fast  

You may have heard that munching on something like celery or lettuce can actually make you burn more calories than it contains, creating a negative calorie effect. Since some vegetables are low in calories high in fiber, and have lots of water, it's easy to assume that eating them all can create a negative calorie balance (15). 

It's definitely good to include fresh fruits and vegetables in your diet, but there’s no evidence that proves these foods require more calories to eat than they contain.  

Lean on whole foods instead of labels

Checking a food label and ingredient list is a good habit for overall health. However when it comes to the calories and nutrient breakdown, keep in mind that the numbers may not be exact. The Food and Drug Administration (FDA) allows calorie counts to be reported 20% in either direction (16). Meaning if a food is labeled as 100 calories, it can be as low as 80 or high as 120 calories. 

For long-term health, optimal performance, and increased thermogenic effect of food, make sure the calories you eat matter by using a food tracker app. Lifesum will help you record your overall calorie intake and identify habits to help you boost your calorie burn!

All of the content and media on Lifesum is created and published for information purposes only. It is not intended to be used as a substitute for medical advice or treatment. Users should always consult with a doctor or other health care professional for medical advice.