(4 minute read)
It is finally time to pop that big question - are all calories equal?
Is there more to calories than meets the eye? When it comes to weight loss is calories in vs calories out all that matters? Let’s answer all these questions.
Calories are the energy that comes from the food we eat, when we do exercise we burn more calories and when we sit on the couch we burn fewer calories to keep our body ticking over. If we just look at the definition of a calorie in food, then yes it would seem every calorie is the same; A calorie is the amount of energy needed to raise 1gram of water to room temperature by 1 degrees Celsius. All calories do that equally, however, the body doesn’t treat all calories from food the same.
Different macronutrients contain different calories per gram, protein and carbohydrate have 4 calories per gram, whereas fat has 9 calories per gram and alcohol 7 calories per gram.
The thermic effect is caused by energy being required to digest and absorb the nutrients in the food you eat. Protein produces the highest thermic effect, so when you eat a meal high in protein it uses more calories to digest and absorb the food.
It has been seen with studies that people eating higher protein and sometimes carbohydrate meals have had a higher resting energy expenditure than high-fat meals - sometimes by as much as 35%!
Staying full and feeling full:
Protein has been seen to reduce hunger and help you feel fuller, ultimately reducing the number of calories you are likely to consume in a day. With carbohydrates, high fibre carbohydrates help you feel fuller and keep you full for longer over and above simple sugars.
So you can see so far that some macronutrients not only help burn more calories but also may help keep you less hungry and fuller for longer.
Insulin sensitivity and glycemic index:
Insulin is a hormone responsible for nutrient storage, especially carbohydrate (glycogen). Too much carbohydrate (glycogen) and too little exercise, glycogen can be stored as fat.
Exercise improves insulin sensitivity and helps prevent carbohydrates from being stored as fat.
Glycemic index measures how food impacts blood sugar levels, and thus insulin response and sensitivity. A diet high in high glycemic index foods will increase blood sugar levels and can impair insulin sensitivity resulting in more potential fat accumulation. As you get older and if you start to experience insulin sensitivity this may be something to think about.
Exercise and metabolism:
Intense exercise has been seen to increase metabolism for periods of up to 38 hours following the exercise session. Therefore the m
uscles are more sensitive to take-up and use the protein and carbohydrates in this period following exercise.
In answer to the questions posed earlier:
While yes all calories are equal, the body acts differently with calories from different sources.
Is there more to calories than meets the eye?
As you can see there are a lot of factors that go into a calorie being a calorie when it comes to food, as they all affect the body in different ways. Calories from different sources have different values to your body.
When it comes to weight loss is calories in vs calories out all that matters?
While you may still lose weight on a calorie deficit eating just sweets and cake this would not be good weight loss, it would affect your body in other ways and could cause other health issues, preventing long term weight loss. Eating a balanced diet with a variety of foods and nutrients taking into account the above factors, you may lose a lot more fat and feel better for it as well as potentially boosting the calories your burning and thermic effect of food digestion, helping to keep the weight off. So yes there are other factors to consider other than just calories in vs calories out.
Focus both on food quality and energy balance!
BSc Sports Science, Women’s Fitness Specialist and Personal Trainer