What are calories?
- The approx. amount of energy needed to raise the temperature of one gram of water by one degree at a pressure of one atmosphere.
- Kcal is known as the food calorie, its equal to 1000 small calories.
Protein: 4 kcal/g
Carbohydrates are to be stored as glycogen.
Fat will be stored as adipose tissue or intracellular fat stores.
Protein will be stored as proteins.
Introducing thermodynamics (the relationship between heat and other forms of energy):
When we eat food, we consume energy, and our systems internal energy changes due to the law of conservation of energy. So when people say that you can eat more and not gain weight, this cannot be true. Energy cannot be created or destroyed, it can only be transformed from one form into another.
So if you eat too much, you’ll store energy = body fat.
So in that sense, the calorie in vs calorie out is right, but the body responds directly and indirectly. I.e. if you consume a high protein diet you’ll have a high thermic effect of food (TEF) which means you’ll need to use more energy to store protein than you would fats or carbohydrates.
Indirectly when someone says they increased their food and lost weight, this isn’t your metabolism ‘firing’. You’ve given the body more energy to work with, which will result in higher intensity training or increased none exercise activity thermogenesis (NEAT) throughout the day.
If you reduce your calories too far, the body will adapt in numerous ways to try maintain the current body fat stores (homeostasis). A large deficit will see a huge reduction in energy and you’ll find the persons overall NEAT will reduce, training intensity and general fidgeting.
Finally, if you’ve lowered your calories and still didn’t lose weight… again the body is always trying to maintain homeostasis. Small changes such as a 250-300 calorie deficit won’t facilitate a shift in weight, it needs to be 500-1000 calories. The same as if you have a big Sunday diner you’ll often feel warm and flustered afterwards due to the physiological change, just the other way around.
So the calories in vs calories out cannot be disputed but there are more variables to consider than just that. The same as focusing on weight loss, when everyone’s goal is is usually muscle retention and fat loss. So the type of diet to formulate that deficit is important to dictate body composition, i.e. as a rule of thumb.
Calories in vs calorie out will determine weight loss
Macronutrients ratios chosen will determine the nature of weight loss
Whether you create the deficit through high fat / low carb or high carb / low fat, makes no difference on total weight loss. Although its important to take into consideration that higher protein diets increase satiety and TEF which so help weight loss.