Cause Of Weight Gain And How To Lose It In Just Two Weeks!
Thermic effect of food (abbreviated as TEF), also known as specific dynamic action (SDA) of a food or dietary induced thermogenesis (DIT), is the amount of energy expenditure above the resting metabolic rate due to the cost of processing food for use and storage. Simply, it's the energy used in digestion, absorption and distribution of nutrients. It is one of the components of metabolism along with resting metabolic rate and the exercise component. A commonly used estimate of the thermic effect of food is about 10% of one's caloric intake, though the effect varies substantially for different food components. For example, dietary fat is very easy to process and has very little thermic effect, while protein is hard to process and has a much larger thermic effect.
Factors that affect the thermic effect of food
The thermic effect of food is increased by both aerobic training of sufficient duration and intensity and by anaerobic weight training. However, the increase is marginal, amounting to 7-8 Calories per hour. The primary determinants of daily TEF are the number of meals consumed per day, the size of the meals and the composition of the meals ingested.
Although some believe that TEF is reduced in obesity, discrepant results and inconsistent research methods have failed to validate such claims.
Types of foods
The thermic effect of food is the energy required for digestion, absorption, and disposal of ingested nutrients. Its magnitude depends on the composition of the food consumed:
Carbohydrates: 5 to 15% of the energy consumed
Protein: 20 to 35%
Fats: at most 5 to 15 %
Raw celery and grapefruit are often claimed to have negative caloric balance (requiring more energy to digest than recovered from the food), presumably because the thermic effect is greater than the caloric content due to the high fibre matrix that must be unraveled to access their carbohydrates. However, there has been no research carried out to test this hypothesis and a significant amount of the thermic effect depends on the insulin sensitivity of the individual, with more insulin-sensitive individuals having a significant effect while individuals with increasing resistance have negligible to zero effects.
The Functional Food Centre at Oxford Brookes University conducted a study into the effects of chilli and medium-chain triglycerides (MCT) on Diet Induced Thermogenesis (DIT). They concluded that "adding chilli and MCT to meals increases DIT by over 50 % which over time may accumulate to help induce weight loss and prevent weight gain or regain".
Australia's Human Nutrition conducted a study on the effect of meal content in lean women's diets on the thermic effect of food and found that the inclusion of an ingredient containing increased soluble fibre and amylose did not reduce spontaneous food intake but rather was associated with higher subsequent energy intakes despite its reduced glycaemic and insulinemic effects.
Measuring TEF
The thermic effect of food should be measured for greater than or equal to five hours.
The American Journal of Clinical Nutrition published that TEF lasts beyond 6 hours for the majority of people
Processed foods and TEF
Research has found that the thermic effect of food contributes to the fact that calories may not all be equal in terms of weight gain. In one study, seventeen subjects ate, on two different days, two bread-and-cheese sandwiches that were the same in terms of calories (the subjects were free to choose either 600 or 800 kcal meals), but one was ″whole food″ (a multi-grain bread, containing whole sunflower seeds and whole-grain kernels, with cheddar cheese), while the other was ″processed food″ (white bread and a processed cheese product). For each subject, the researchers measured the extra energy, beyond that due to the basal metabolic rate, that the subject expended in the six hours following the consumption of the meal; that energy divided by the energy content of the meal was (after multiplying by 100) reported as the percent DIT coefficient. The average percent DIT coefficient for the ″whole food″ sandwiches was (19.9±2.5)%, while for the ″processed food″ sandwiches, it was (10.7 ±1.7)%—a difference of a factor of 2. When the DIT values are subtracted from the total meal energy, it follows that the subjects obtained 9.7% more net energy from the ″processed-food″ meal than from the ″whole-food″ one.
DIET INDUCED THERMOGENESIS
The increase in heat production by the body after eating. It is due to both the metabolic energy cost of digestion (the secretion of digestive enzymes, active transport of nutrients from the gut, and gut motility) and the energy cost of forming tissue reserves of fat, glycogen, and protein. It can be up to 10-15% of the energy intake. Also known as the specific dynamic action (SDA), thermic effect of foods, and luxus konsumption.
THERMIC EFFECT OF FOOD
When we have a meal, our body temperature tends to rise. This is because we need to expend energy to digest food, and to absorb and assimilate nutrients. Consequently, the calories available to you from food may not correspond exactly to the calorific content described on a food label. It is estimated that diet induced thermogenesis uses between 5 and 10 per cent of a meal's total energy, but the exact amount varies with the type of food. Our bodies seem to be relatively inefficient at utilizing carbohydrate, and less energy is available from it for storage and growth. Diet induced thermogenesis accounts for up to 23 out of every 100 calories when we eat complex carbohydrates, but only 3 out of every 100 calories when we eat pure fats. This is one reason fatty meals are so fattening!
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