I’m sure many of us would agree that fruit (in its different varieties) offers an array of health benefits.
However, surprisingly, when trying to lose weight and/or build muscle, eating fruit can sometimes be a double-edged sword. By that, I mean it can either work for you or against you.
Now, before I continue, it’s worth mentioning that the reason why I have decided to address this topic is because I have recently received a tonne of emails/tweets asking me what I eat/drink after a workout – and in addition to a protein shake, if fruit is OK. Besides consuming protein post-workout, it’s just as important to replenish muscle glycogen (carbohydrates stored within the muscle). The quickest way to achieve this is to refeed the body with a fast-acting carbohydrate/simple sugar.
As you may know, fruit is made up of sugars, of which come in a variety of forms; glucose, sucrose, lactose, maltose… to name but a few! Although fruit contains glucose and sucrose, it also contains fructose – a type of sugar that you may often hear being described as “naturally occurring”. However, not all sugars are created equal and fructose is no exception. More on the reverse.
Carbohydrates, as sugars are, have the capacity to do 3 things: provide immediate energy, replenish muscle and/or liver glycogen, or be stored as fat – that’s interesting; “muscle and/or liver glycogen”. Of course, following a workout, your immediate priorities should be to replenish muscle glycogen, whilst restoring a positive nitrogen balance. As mentioned earlier, combining a protein shake (whey isolate) with a fast-acting carbohydrate/simple sugar is the quickest way to achieve this – timing is everything here.
And this is where fructose falls short. Firstly, fructose is ranked lower on the glycemic index (GI) than other sugars are, and Since GI measures the effects of carbohydrates on blood sugar, this suggests that fructose is not as readily digested as glucose etc. is. This is important because fast-acting carbohydrates/simple sugars help maximize protein synthesis via an insulin spike, which is exactly what you want post-workout. Secondly, unlike glucose, fructose is less effective at replenishing muscle glycogen and instead, is more likely to replenish liver glycogen – the opposite of what you want post-workout.
If, however, you’re on a budget and fruit is your only option, then opt for a banana. Bananas contain glucose and fructose at an approximate 2:1 ratio. If you happen to be training in the evening, then bananas are great; yes, the fructose may replenish liver glycogen but this in turn can help prevent blood sugar levels from crashing – helpful for those who get late night cravings.
As you would expect, fruit is an ideal option for breakfast. When we sleep, our blood sugar levels drop, consequently causing the brain to release stress hormones. To counteract this, our bodies tap into our liver glycogen by converting it to glucose and releasing it into the bloodstream, which in turn helps to normalize blood sugar levels. This process is known as glycogenolysis. As a result, upon waking, our liver glycogen stores are usually depleted – and this is where eating fruit can help.
As I stated at beginning, fruit is a double-edged sword and I now hope that you understand what I meant when I said “it can either work for you or against you”.