What is the Thermic Effect of Food (TEF)?
The thermic effect of food, also known as diet-induced thermogenesis (DIT) or specific dynamic action (SDA), refers to the increase in metabolic rate that occurs after eating. It represents the amount of energy required to digest, absorb, transport, and store the nutrients from food . TEF accounts for approximately 10% of the total daily energy expenditure in healthy adults eating a mixed diet . However, the actual TEF can vary depending on factors like age, meal timing, and the macronutrient composition of the meal .
TEF of Different Macronutrients
The thermic effect differs for each macronutrient:
- Protein: 20-35% of calories burned through processing
- Carbohydrates: 5-15% of calories burned through processing
- Fat: 0-5% of calories burned through processing
So protein has the highest thermic effect, followed by carbohydrates, while fat has the lowest. This means that for every 100 calories of protein consumed, 20-35 calories are used just to process it .
Factors Affecting TEF
Several factors can influence an individual’s TEF:
- Meal size: Larger meals tend to have a higher thermic effect than smaller, more frequent meals
- Macronutrient composition: High-protein and high-carbohydrate meals have a greater thermic effect than high-fat meals
- Age: TEF may decrease with age
- Physical activity level: Exercise can increase TEF
- Genetics and individual variation
Importance of TEF
Understanding the thermic effect of food can be useful for weight management. Consuming foods with a higher thermic effect, like lean proteins and complex carbohydrates, may help slightly boost overall calorie expenditure. However, TEF is just one component of total daily energy expenditure, alongside resting metabolic rate, non-exercise activity thermogenesis (NEAT), and exercise. A balanced approach considering all these factors is important for overall health and weight management.
What is the relationship between the thermic effect of food and metabolism?
Your metabolism refers to all the chemical processes in your body that convert the food and drinks you consume into usable energy. TEF is one component of your total daily energy expenditure (TDEE), which represents the number of calories your body burns each day. The other components of TDEE are:
- Basal metabolic rate (BMR): The calories burned at rest to maintain basic bodily functions
- Non-exercise activity thermogenesis (NEAT): The calories burned through daily activities and fidgeting
- Exercise activity thermogenesis (EAT): The calories burned via intentional exercise
So TEF contributes to your overall metabolic rate and the total calories you expend each day.
TEF Occurs During Digestion and Nutrient Processing
When you eat, your body has to expend energy to digest, absorb, transport, and store the nutrients from that food. This increase in metabolism is highest in the 4 hours following a meal, known as the postprandial period. The initial steps of food metabolism, like digestion and absorption, require energy in the form of ATP (adenosine triphosphate). The amount of ATP used in these processes determines the thermic effect of that particular food.
TEF Varies by Macronutrient
As mentioned earlier, protein has the highest thermic effect (20-35%), followed by carbohydrates (5-15%), and then fat (0-5%). This means that for every 100 calories of protein you eat, 20-35 of those calories are used just to process the protein. So eating a higher protein diet can slightly increase your metabolic rate through TEF compared to a lower protein diet. However, the overall impact is relatively small.
TEF is Just One Factor in Energy Balance
While TEF does influence your metabolism and overall calorie expenditure, it’s important to keep in mind that it’s just one piece of the puzzle. Your basal metabolic rate accounts for the majority (60-75%) of your daily calorie burn. Factors like your age, sex, body composition, and genetics have a much greater impact on your BMR and TDEE than the thermic effect of the foods you eat. And ultimately, consuming more calories than you burn will lead to weight gain, regardless of the food’s thermic effect. So while understanding TEF can be useful, it’s not a magic bullet for boosting metabolism or losing weight. A balanced diet and regular physical activity are still the cornerstones of a healthy metabolism.
There’s also insulin..
The key points about insulin and its relationship to the thermic effect of food (TEF):
Insulin’s Role in Blood Sugar Regulation and Energy Storage
Insulin is produced by the pancreas and released into the bloodstream in response to rising blood glucose levels, typically after eating. Its main functions are to:
- Allow glucose to enter cells for energy: Insulin attaches to receptors on cells, signaling them to take in glucose from the bloodstream.
- Promote energy storage: Insulin signals the liver and muscles to convert excess glucose into glycogen for storage. It also promotes the storage of energy as fat.
- Regulate blood sugar levels: Insulin works in tandem with glucagon to maintain stable blood glucose levels. When blood sugar is high, insulin lowers it; when it’s low, glucagon raises it.
The Double-Edged Sword of Insulin
While insulin is essential for maintaining normal blood sugar levels, it also has a role in fat storage. Insulin inhibits lipolysis (the breakdown of fat) and promotes lipogenesis (the creation of fat).
Foods that cause a rapid and significant increase in blood sugar, like refined carbohydrates, tend to stimulate a larger insulin response. If you consistently consume more calories than you burn, this can lead to excess energy being stored as fat.
Insulin and the Thermic Effect of Food
The thermic effect of food (TEF) refers to the increase in metabolic rate after eating, as your body expends energy to digest, absorb, and process nutrients. Protein tends to have the highest thermic effect, followed by carbohydrates, and then fat.
While insulin’s role in fat storage may seem to counter the metabolic boost of TEF, it’s important to remember that overall calorie balance is the key determinant of weight gain or loss. If you’re consuming fewer calories than you burn, you’ll lose weight, even if some of those calories trigger an insulin response. While it does play a role in fat storage, this doesn’t negate the thermic effect of food or mean that insulin will automatically lead to weight gain.
What influences a foods thermic effect?
1. Age
TEF may decrease with age due to changes in digestive capabilities and a decrease in sympathetic nervous system activity. Older adults may experience a reduced thermic effect compared to younger individuals.
2. Physical Activity
The impact of physical activity on TEF is still unclear, but it does influence overall energy expenditure. Some research suggests that TEF may be altered in trained individuals due to differences in body composition, physical fitness, and insulin resistance.
3. Meal Size
Larger meals tend to result in a greater thermic effect compared to smaller meals. Higher food intake can increase energy expenditure by more than 10%.
4. Meal Composition
The macronutrient composition of a meal significantly influences the magnitude of TEF. Meals high in protein and complex carbohydrates have a greater thermic effect compared to those high in fat, as fat has little impact on TEF.
5. Meal Frequency and Timing
Contrary to popular belief, consuming smaller, more frequent meals does not necessarily boost metabolism or aid in weight loss. Evidence suggests that TEF is higher when consuming a single, large meal compared to several smaller meals.
6. Individual Factors
Factors such as sex, body composition, genetics, certain medical conditions, and medications can all affect how many calories an individual burns during digestion and influence their TEF.
While the thermic effect of food (TEF) does play a role in boosting your overall calorie burn and can be a helpful tool in your weight loss arsenal, it’s essential to recognize that its contribution is relatively modest compared to other factors that influence your energy balance.
Top 10 Foods with High Thermic Effect
1. Lean Meats
Protein has the highest thermic effect of the macronutrients, with 20-30% of calories being expended during digestion . Lean meats like chicken, turkey, duck, pork, and red meat are excellent protein sources that can help increase thermogenesis .
2. Eggs
Eggs are another great protein-rich food, with over 6g of protein per egg. A high-protein diet including egg whites, turkey, cottage cheese and tuna was found to double postprandial thermogenesis compared to a high-carb diet .
3. Wild-Caught Seafood
Fatty fish are not only rich in omega-3s that reduce inflammation, but their high protein content also boosts the thermic effect. Fish oil may also enhance the thermogenic action of thyroid hormones .
4. Cottage Cheese
This protein-packed dairy product is a bodybuilding staple that provides an abundance of vitamins and minerals in addition to its thermogenic benefits .
5. Chili Peppers
The capsaicin in chili peppers like cayenne has been shown to promote thermogenesis, boost metabolic rate, increase fat oxidation, and reduce appetite .
6. Legumes
The combination of protein, complex carbs, and fiber in legumes contributes to a slower digestion, increased satiety, and a notable thermic effect . Their fiber also improves glycemic control.
7. Sweet Potatoes
In addition to providing beta-carotene and fiber, sweet potatoes may reduce insulin resistance and inflammation while boosting levels of the fat-mobilizing hormone adiponectin .
8. MCT Oil
Unlike other fats, the medium-chain triglycerides in MCT oil are rapidly metabolized and converted to energy in the liver. The C8 and C10 MCTs abundant in MCT oil may enhance daily energy expenditure .
9. Nuts
Despite being calorie-dense, nuts provide healthy fats, protein, and a thermic effect. The lipids in nuts are absorbed more slowly, providing a sustained energy source that fuels thermogenesis .
10. Turmeric
The curcumin in turmeric has been extensively researched for its anti-obesity effects. It interacts with fat cells, improves glycemic control, breaks down fatty acids, and suppresses inflammation in adipose tissue . While these thermogenic foods can provide a metabolic boost, it’s important to remember that the effects are modest in the context of overall energy balance. A nutritious, balanced diet and regular physical activity remain the foundations of healthy weight management.
The key takeaways:
- Focus on overall diet quality: Prioritize whole, minimally processed foods that provide a balance of protein, complex carbohydrates, healthy fats, and fiber. This will help you feel satisfied, maintain stable energy levels, and support overall health.
- Incorporate thermogenic foods: Including foods like lean meats, eggs, legumes, and spicy peppers in your diet can provide a modest metabolic boost and support your weight management efforts. However, don’t rely on these foods alone to achieve your goals.
- Stay active: Regular physical activity is crucial for maintaining a healthy weight and promoting overall health. Aim for at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week, along with strength training at least twice a week.
- Consider supplements carefully: While high-quality fat burner supplements like Burn Lab Pro can provide additional support, they should never be seen as a replacement for a healthy diet and lifestyle. Always consult with a healthcare professional before starting any new supplement regimen.
Remember, sustainable weight loss and improved body composition come from a long-term and consistent approach to healthy eating and regular physical activity. Incorporating foods with a high thermic effect can be a helpful addition to your strategy, but they’re just one piece of the puzzle. Stay focused on your goals, be patient with yourself, and celebrate the small victories along the way. You can only achieve lasting results and improve your overall health and well-being with dedication and a balanced approach.