In Part 1, we looked at the the importance of energy balance, and situations which can affect the fate of calories.
In this part, we’re going to look at the role of diet composition on calorie intake, and what you can emphasise in your diet to control intake, without calorie counting.
Another argument consistently put forward by the ‘a calorie is not a calorie’ camp is that calories don’t matter, or don’t need to be counted, as long as you’re eating the ‘right’ foods.
This, again, is heard loudest from low carb or Paleo dogmatists and posits that once carbs are low, you can eat all the dietary fat and protein you want and not gain fat.
This logic is flawed.
Simply because a particular way of eating doesn’t require you to count calories, or allows you to lose weight without paying conscious attention to calories, does not mean that calorie intake is irrelevant.
People who lose weight without counting calories on a low carb or Paleo style of diet do so because the increased protein keeps them fuller, for longer, and facilitates an overall reduction in calories. 
This is not exclusive to meat-based diets. High protein vegetarian diets cause the same fullness and facilitate weight loss equal to high protein meat-based diets. 
Fibre content in a diet is also a significant factor. This is relevant to vegans, vegetarians and meat inclusive diets alike; high fibre content increases fullness and reduces hunger levels. 
The contention that a calorie isn’t a calorie once you’re eating certain foods is a smokescreen. It masks the fact that a particular way of eating provides a means of consuming fewer calories without having to count.
This is where diet composition does matter. This is the crux of the issue: in the context of all the science on calories, the fact is that we are not living in metabolic wards or subjects in a controlled trial.
We need real world applicability.
The fact is that in free-living conditions, diet composition influences energy intake and energy balance, hunger and fullness. 
The real-world relevance goes further, in that the most important factors in influencing calorie intake and promoting sustainable weight loss are not confined to one particular dietary approach.
Whether you are a vegetarian or a dedicated carnivore, the principles remain the same: high protein, high fibre, and low energy density.
The logical error we need to avoid making is assuming that eating a diet that facilitates a free-living reduction in calories is evidence that a calorie is not a calorie.
So be wary of anyone telling you that you can eat as much of anything as you want and not put on weight. A calorie is still a calorie, and whether you’re vegetarian or low-carb, it’s the dietary factors which influence fullness and hunger that facilitate weight loss in real-world conditions.