We all know that calories are a measure of energy but what is rarely discussed is the thermal effect of food (TEF), or more simply put, the energy cost it takes to digest the food you eat. Focusing in on this point, there was an interesting scientific study done to determine if processed food had a greater or lesser thermodynamic efficiency than a comparable whole food.
In other words which foods are more effective in assisting with weight loss, processed or unprocessed foods?
The foods used in the comparative study were sandwiches. One consisted of white bread with processed cheese and the other an unprocessed multi-grain bread with cheddar cheese. Both meals contained 800 calories and the macronutrient composition was similar.
The digestion and absorption of a meal induces a small increase in energy expenditure. This process is known as the thermic effect of food, dietary thermogenesis, or diet-induced thermogenesis and is accountable for approximately 10% of our total daily energy expenditure. This means we burn calories by simply eating - nice!
Eating protein produces greater dietary thermogenesis than eating fat. The dietary thermogenesis of carbohydrates falls somewhere between the two. The macronutrient percentages are as follows:
Protein = 20-30%
Carbohydrates = 5-10%
Fats = 0-3%
For example, if you eat 100 calories from protein, your body uses 20-30 of those calories to digest and absorb the protein. You’d be left with 70-80 calories. Carbohydrate would leave you with 90-95 calories, and Fat would give you 97-100 calories.
Therefore protein is one of the primary factors in determining dietary thermogenesis. It is also the most significant influencing macronutrient in determining dietary satiety, or a feeling of fullness from eating. Hence, protein is instrumental in regulating body weight because of its primary role in dietary thermogenesis and related satiety.
This scientific study showed diet-induced thermogenesis is ~47% lower following a processed food meal compared to a calorie matched whole food meal. So 100 calories of processed food ends up being MORE calories than 100 calories of unprocessed (whole) foods.
Based on this studies results we can see why the quality of food ingested matters in determining weight gain and loss.
When in doubt as to what a whole food is....... read the ingredients label. If you don't recognize the ingredients or the list is so long your eyes hurt, chances are good it is processed.
Seriously, most folks know what whole foods are but your best bet is to head over to the produce aisle at the grocery store for your nutrient-dense carbohydrates. Diary, beef, fish, chicken, pork are all great protein sources. For those folks who are vegetarian and vegan there are oodles of protein options which can augment plant-based proteins in order to build a balanced meal.
Find out how Metabolic Efficiency Training (nutrition) can assist in optimizing your health and your fitness goals! Simply go to insideouthp.com and send an email from the Contact page.
CASE STUDY: (To read the case study on PubMed)
Postprandial energy expenditure in whole-food and processed-food meals: implications for daily energy expenditure.