Can the processing of food reduce energy expenditure?
Foods provide our body with energy (i.e. calories). But the digestion and absorption of a meal also cost energy. This process is called diet-induced thermogenesis and is accountable for approximately 10% of our total daily energy expenditure.
However, not all nutrients increase energy expenditure to the same extent. For example, protein causes the largest increase in energy expenditure (20-30%), followed by carbohydrates (5-10%), and fat causes only a 0-3% increase. But diet-induced thermogenesis may not be only dependent on the nutrient composition of a meal.
This study investigated diet-induced thermogenesis following a whole food (unprocessed) or processed meal. The processed meal was a white bread sandwich with processed cheese and the unprocessed meal was multi-grain bread with cheddar cheese. Both meals contained 800 kcal and the macronutrient composition was similar.
Diet-induced thermogenesis was ~47% lower following a processed food meal compared to the calorie-matched whole food meal.
While this sounds like a huge effect, you would have to translate it to calories to assess the practical relevance. With a daily caloric intake of 2500 kcal x 10% (diet-induced thermogenesis) x 50% (if all food would be processed), it translates to ~125 calories on a day.
Go to the next infographic in the dieting series:
Ultra-processed foods cause weight gain?
It’s worth noting that in this experiment, they used sandwiches and the difference was wholemeal bread vs white and cheddar vs processed cheese slice. That’s not a huge difference compared to say a burger and chips vs an isocaloric 3 bean casserole with brown rice. In this latter example there is a significant amount more fibre tying up the nutrients. Not only is the TEF increased but available calories is lower from the start.
Agreed