There is so much conflicting information out there about carbohydrate consumption that it is easy to see why many people are confused. While most know how many grams of protein they need (I covered it in this post, but about 2-3 grams per kilogram of body weight) and many assume their intake of healthy fats is adequate, there is no prescribed level of carbohydrates that will work for everyone.
Some people – including whoever wrote my PT certification coursework – advocate high carbohydrate diets, where up to 60 per cent of your total calories come from carbohydrates. In my opinion, that number is far too high as it results in only approximately 10 per cent of calories coming from protein.
What effect do carbohydrates have on the body?
There are two types of carbohydrates, simple and complex. The difference between the two is based on structure, and the effect each has on blood sugar levels. Simple carbohydrates such as processed sugars, white flour-based products and even so-called healthy items such as fruit and rice cakes produce a faster insulin response.
The only time you should be having fast-digesting carbohydrates is immediately post-workout, when your depleted glycogen stores need to be replenished. For example, I eat white rice after every workout. The only time I have fruit is in my post-workout meal.
Complex carbohydrates such as wholemeal and wholegrain products, vegetables and pulses cause a slower, sustained insulin response. Both forms of carbohydrates are converted into glucose upon entering the body. When glucose is detected in the blood stream, insulin is released and enables muscle and fat cells to take in glucose. Without insulin, we would all experience death by pasta!
When blood sugar levels are high, glucose is converted to glycogen and stored in the liver or muscles until needed. However, only around 500 grams of glycogen can be stored in the body. Excess glucose will be stored as body fat – and fat cells unfortunately have an almost limitless storage capacity.
The problem many people suffer from is that they are hooked on a cycle of eating refined carbohydrates. Eating the wrong type of carbohydrate causes blood sugar levels to become very high, but then suddenly drop. This leaves you feeling tired, lacking concentration and hungry. You then eat more simple carbs to satisfy your appetite, but the cycle only continues. Because our cells have already received enough glucose, the majority of these carbohydrates are stored as fat.
Glucagon opposes the action of insulin, by releasing nutrients stored in cells. However, glucagon is only released when insulin levels are low. If insulin levels are constantly high then everything taken into the body will be stored while the body will never be able to access the huge stores of energy it already has. This leads to an unlimited accumulation of body fat.
Aside from choosing complex carbohydrates, there are a number of other things you can do to encourage a slower insulin response. For example, including protein and fibre with every meal slows absorption. The most important factor, however, is monitoring the amount of carbohydrates you eat at any one time.
So how many carbohydrates should you eat?
Unfortunately, there is no one-size-fits-all answer. Everyone has a different insulin sensitivity; that is, the amount required to return blood glucose levels to normal. I’m sure everyone knows someone who is rail thin and seems to constantly eat refined carbohydrates. Similarly, there are others who simply look at the bread basket and gain a kilo. For those that have to secrete a greater amount of insulin, fat will be prevented from being broken down for longer than normal.
Because of the cellular processes described above, there is a very fine line between consuming the right number of carbohydrates and a surplus amount. Just as consuming excess carbohydrates will have a damaging effect on the body, taking in an inadequate amount of carbs brings its own negative consequences.
In the short-term, those following a low-carbohydrate diet will see rapid fat loss as the body starts using the energy stored in fat cells. However, after about a month of following such a diet, the body enters starvation mode and holds on to as much fat as possible as the fat cells become more efficient at storing energy. This ultimately stalls weight loss. When a ‘normal’ diet is resumed, people store fat at an even greater rate. Because much of the initial weight loss is water and muscle mass (as the muscles have to be broken down to fuel the body) most people will end up heavier than when they started – with more body fat and less muscle!
I know from personal experience that neither high- or low-carbohydrate diets do my body any favours. I do not track calories or macros, but today I worked out my current macronutrient split. In line with what I assumed, 39 per cent of my calories come from protein, 31 per cent from carbohydrates and 30 per cent from fat. Many others follow a 40:30:30 split, where the largest portion of their diet is made up of carbohydrates, but over the years I have learnt that 40 per cent carbohydrates is too high for me.
Eating every two to three hours ensures blood sugar levels remain steady and our bodies’ absorption capabilities are not overloaded.
If you’re trying to build muscle, first determine your Basal Metabolic Rate (BMR). This is the number of calories your body needs just to survive. Then add any calories you are burning off through exercise. For example, my BMR is around 1500 calories. To maintain my current weight, I need to eat about 2200 calories a day. If I want to build muscle, I need to be in a calorie surplus by eating around 2400 calories a day.
Start with an additional 200 surplus calories per day. Follow a 40:30:30 macronutrient split, where carbohydrates make up your dominant energy source (I used Livestrong.com’s MyPlate to determine my macros). For example, if your target is 2400 calories a day, 960 of those should come from carbs – or 240 grams of net carbohydrates.
Watch how your body adapts. You need to give a new diet plan at least six weeks to see progress. If you’re gaining too much fat, try dropping your carbohydrates and calories very slightly.
If you’re trying to purposely gain muscle you can’t just assume that eating a ridiculous amount of protein is going to make it happen. The body will not make muscle growth its top priority if it thinks it is lacking fuel. Your body needs carbohydrates to build new muscle – you just have to choose complex sources and not eat too many.
How many grams of carbohydrates do you eat daily? Have you ever followed a high- or low-carb diet?