Researchers from Queen's Medical Centre have reported that subjects who consumed meals at odd times and with no consistency showed significantly less "thermic effect of food" than those who ate at regular intervals.
It is also important to note that the types of food you eat during these times can affect your metabolic rate as well.
For example your body metabolizes carbohydrates best in the morning once you wake up and after workouts is also a great time to metabolize carbohydrates.
The reason your body uses carbohydrates best in the morning and after workouts is because there is depletion of glycogen storage from fasting all night and the carbohydrates used during your workouts.
In the morning your cortisol levels are also elevated from fasting and that is a bad thing if your cortisol levels get too high. This encourages fat storage so to combat that you increase your insulin levels to combat the cortisol.
Now I am not talking about spiking your insulin level by gorging on carbs and sugar. Though you should incorporate enough carbs into your meal plans at these specific times to elevate insulin slightly, which then lowers the cortisol level in your body.
The fear about eating sugar in your healthy meal plans is that it increases insulin levels and that promotes fat storage. This is true to an extent. However, most people don't know or fail to recognize that there are many mechanisms and also nutrients that play vital roles in determining your fat loss. Fiber, protein and fat all play a role in regulating insulin levels and controlling other key hormones specific to fat loss.
When you apply a few small principles of nutrient timing to your healthy meal plans it can go a long way to providing you sustained weight loss.