To start with I shall clarify my message on carb timing:
Avoid carbs at breakfast! Instead opt for fattier choices through the morning and at lunch and save your carbs for post workout or in your evening meal. You don't even need to eat carbs everyday, for some goals it may be beneficial to only eat carbs one evening a week.
Now to explain why this is my stance! I shall start by saying that carbohydrate is the only non-essential macronutrient. Our bodies are perfectly capable of producing enough glucose for our brain to function well. In fact mental performance and aerobic physical performance is often enhanced when using fat as a primary fuel source. I want to get this in early doors to try and dispel the myth that carbs are in any way necessary - they aren't! This being said we can use carbs sensibly to improve body composition and performance as well as keeping ourselves happy as, it can't be argued, carbs are bloody delicious!
So to understand why we should eat our carbs at night we need to look at the roles of two hormones; Insulin and Cortisol. Insulin is the hormone that shuttles blood sugar to our cells for energy and storage, this is why it is released when we eat carb (and sometimes protein) based food. Insulin is an anabolic hormone meaning that it builds things. Cortisol, on the other hand, is a catabolic hormone meaning that it breaks things down. Cortisol is known as the stress hormone as we release it when in a stressful situation in order to mobilise our energy stores and ready several other bodily functions. Cortisol has a bad reputation because of this link with stress and is feared by those who are trying to gain muscle as it is famous for breaking muscle down. Whilst this is true it is only the case in certain contexts. Cortisol has different actions dependant on whether insulin is present. If insulin is present then it will encourage fat storage and will catabolise muscle. When insulin isn't present cortisol will protect muscle tissue and mobilise fat from cell storage.
Now when we wake in the morning we are in a fasted state so our insulin levels are low, our cells are very sensitive to insulin because of this. This insulin sensitivity decreases through the day until the cells are relatively insulin resistant in the evening, meaning they are less capable of taking glucose from insulin. Our cortisol on the other hand peaks when we wake and then drops through the day.
Whilst insulin resistance is higher in the evening our muscles have a clever trick to bypass this, called non-insulin mediated glucose transport, they have special proteins which are able to take glucose from the bloodstream. This effect is greatly enhanced by resistance training.
So putting the facts above together can we see how it would be beneficial to eat carbs in the evening?
If we followed the mainstream advice to have a carb heavy breakfast then we would be spiking insulin at a time when cortisol is high. This would promote fat storage and muscle breakdown. What's more our fat cells are extra sensitive to insulin so are more likely to store this carb meal as fat.
Take my suggestion and have a fat based breakfast, which for me often ends up just being a coffee with coconut oil and thick cream, and we aren't spiking insulin which means that cortisol can do its thing of releasing fat for energy. Then through the day, as we are active, we are creating a situation where our muscles are hungry for energy yet our fat cells aren't. This means that our evening carb meal goes exactly where we want it to.
If you look at studies where this theory is tested you will see that those that eat more calories (particularly carbs) in the morning lose more weight than those that eat them in the evening. This evidence seemingly validates the mainstream advice. If we look at body composition however we see that those in the morning groups lose muscle and often gain some fat where as those in the evening groups maintain or even gain muscle but lose fat. Muscle is denser than fat so the more we have the heavier we weigh which explains why any study in this area needs to look at body composition rather than just weight!
I hope this brief glance at the topic has given you an insight into why I eat this way and recommend clients to do likewise. If you'd like to read further on this area then look up the excellent John Kiefer, whose methods inform a lot of my work. This article by him is a great place to start as it covers this area in a bit more detail: http://articles.elitefts.com/nutrition/logic-does-not-apply-part-2-breakfast/
Tomorrow I will be tackling my thoughts on a macros based approach to nutrition so please check back then for that.