THE THERMIC EFFECT OF FOOD

Weight gain, whether intentional or not, generally occurs over long periods of time, as habitual energy intake exceeds our bodies’ requirements. Because the process for most of us is a relatively slow one (e.g., on average 0.5 kg or 1.1 pounds per year), factors that influence energy balance, even modestly, may be clinically important over time.

As discussed in this month’s What’s New? the three main components of our daily energy expenditure are resting (basal) metabolic rate, physical activity and the thermic effect of food. While most people can consciously increase their physical activity level, most aren’t aware that what you eat and drink can have an effect on the thermic effect of food.

The thermic effect of food is also known as dietary induced thermogenesis and is the increase in metabolism that occurs after we consume a food, meal or drink. For an average adult, it accounts for approximately 10% of total daily energy expenditure. It represents the energy expenditure of processing and storing food/nutrients within our bodies’, as well as the metabolic effects of the influx of nutrients on our bodies’. Evidence suggests that it may be possible to alter the thermic effect of food as a weight-management tool in both research and clinical practice.

Age, physical activity, meal size, meal composition, meal frequency and processing have all been found to influence the thermic effect of food:

• Age: the thermic effect of food may decrease with age.
• Physical activity: regardless of age or body composition, physical activity increases the thermic effect of food.
• Meal size: higher energy intake from a meal results in increased thermic effect of food.
• Meal composition: higher-carbohydrate meals, particularly those with a higher fibre content, increase the thermic effect of food compared to higher fat meals, and in particular those high in saturated fats. Higher protein meals have a higher thermic effect of food than lower protein meals.
• Meal frequency: Consuming the same meal as a single eating event (i.e., a large meal) compared to multiple small meals or snacks increases the thermic effect of food.
• Processed versus minimally processed foods: minimally refined grains increase the thermic effect of food, compared to refined grains.

While this is an area that requires more research, the evidence available to-date suggests that a high fibre, higher carbohydrate diet with adequate protein and a low proportion of saturated fat may increase the thermic effect of food. While the overall effect is likely to be small, taken together, these simple measures may help slow the gradual process of weight gain in adulthood.

Read more:

• Calcagno and colleagues. The Thermic Effect of Food: A Review. J Am Coll Nutr. 2019.
• Quatela and colleagues. The Energy Content and Composition of Meals Consumed after an Overnight Fast and Their Effects on Diet Induced Thermogenesis: A Systematic Review, Meta-Analyses and Meta-Regressions. Nutrients. 2016

Dr Alan Barclay, PhD, is a consultant dietitian and chef with a particular interest in carbohydrates and diabetes. He is author of Reversing Diabetes (Murdoch Books), and co-author of nearly 40 scientific publications, The Good Carbs Cookbook (Murdoch Books), Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment Publishing).

Contact: Follow him on Twitter, LinkedIn or check out his website.