Once food is eaten, it splits into its constituent nutrients such as carbohydrates, proteins and fats. Our body is smart enough to recognize each of these from the profound mixture and treats them separately. Carbohydrates, proteins and fats undergo a different breakdown process requiring varying amounts of energy.
What is this diet induced thermogenesis? How exactly is the food we ingest affecting the way we burn our calories?
Diet-Induced Thermogenesis (DIT) is the production of heat that occurs after eating –which contributes to the body’s resting metabolic rate. DIT is also called the thermic effect of food. Once food is eaten/ ingested , certain processes are kick-started in the body to support the ingestion, digestion, and absorption of nutrients as well as transport of blood. These processes require energy and heat is generated. This phenomenon of energy-burning associated with food consumption is the thermic effect of food.
While BMR contributes up to 70% of the energy expenditure and physical activity up to 20%, DIT is the smallest component accounting for only 3-10% of daily energy expenditure. However, it can play a major role in the development and/or maintenance of obesity.
How to increase te DIT
Two main factors affect the thermogenesis:
- Frequency of meal consumption
- Type of nutrient ingested
Frequency of meals – Like discussed under BMR, eating the same amount of calories across smaller frequent meals boosts the thermogenic effect compared to three large meals.
Type of nutrient– Every ingested nutrient leads to formation of energy molecules called ATP (Adenosine triphosphate. It’s a storage form of energy). But these energy molecules are formed at a cost (i.e. energy released in the form of heat).
Based on this,
- Protein seems to require the most amount of energy in the formation of energy resulting in higher DIT value of 20-30%
- Next energy requiring nutrient is carbohydrate causing an increase in metabolic rate by 5 to 10%
- Fat causes the least wastage of energy with a DIT value of 0-3%
In simple words, it means that if we ingest more proteins, more calories will be burned in order to form the ATP molecules which is favourable for weight loss.
Protein rich meals tend to increase the metabolic rate. Also, food rich in protein provide more satiety or feeling of fullness. Efforts to increase or even maintain higher percentage of fat free /muscle/lean body mass require careful selection of good quality protein in the diet. Hence, we can say that protein plays a key role in body weight regulation through satiety related to diet-induced thermogenesis.
Although this may seem as a complicated concept for the common man to understand, the take home message is that different nutrients trigger the metabolism to varying extent and amongst them protein seems to have the most favourable effect by increasing metabolic rate. So the energy expenditure can be increased by altering this component of the diet.
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Dr Pooja Chhawcharia is the Senior Nutritionist at eKincare with over 7 years of experience in Nutrition education, diet counseling and research. She is a Registered Dietician with the Indian Dietetic Association and Certified Diabetes Educator recognized by the International Diabetes federation . She is also interested in ancillary sciences such as Yoga and Naturopathy.