Introduction to carbohydrates

Carbohydrates are a macronutrient group whose primarily role is to provide us with energy in our daily lives. There are different sources of carbohydrate, which we can split into three main groups:

1. Fibrous carbohydrates – these are carbohydrates that come alongside large amounts of fibre. Typical examples of these types of carbohydrates are most vegetables and fruits.
2. Starchy carbohydrates – these are carbohydrates that have less fibre and more starch. Of the vegetables, we would class potatoes in this group, along with wholegrain foodstuffs such as bread, rice, and pasta.
3. Refined carbohydrates – these are carbohydrates that have been heavily processed, which often removes much of the fibre and micronutrients. Examples of refined carbohydrates include white bread, white rice, and white pasta.

We can determine the effect that carbohydrates have on us by knowing foods glycaemic index (GI). This tells us the effect a food has on our blood glucose. However, a weakness of GI is that it doesn’t take into account a typical portion size of a food; for example, carrots have a higher GI than fettuccini pasta. That’s why we prefer to use glycaemic load (GL), which tells us the effect of a food on our blood sugar per standard portion. The table below shows some common foods, along with their GL and GI scores:

If you search online for “GL food table” you will be able to find much more comprehensive lists.

So how can you use this information alongside your DNAFit results?

The higher your sensitivity to carbohydrates, the more sensitive you are to the negative effects of higher carbohydrate intakes – specifically insulin resistance and fat gain. As such, we would recommend that the higher your carbohydrate sensitivity, the fewer carbohydrates you consume. Individuals with a high sensitivity should focus on getting the majority of their carbohydrates from fibrous sources, whilst those with a low sensitivity can choose more starchy sources.

When it comes to refined carbohydrates, ideally we wouldn’t consume any. However, it’s important that we are pragmatic, and accept that it's not always possible to avoid them completely. The standard recommendation is no more than 10% of your total carbohydrate intake should come from refined sources. The higher your carbohydrate sensitivity, the less refined carbohydrate you should consume.

Like all genetic factors, your carbohydrate sensitivity is also modified by your environment. The more active you are, generally the more carbohydrate you should consume. An elite athlete with a high carbohydrate sensitivity likely requires more carbohydrates on a daily basis than a couch potato with a low sensitivity. However, if and when that elite athlete wants to lose fat, focusing on reducing carbohydrates is likely the best way of achieving this.

You can work out how many grams of carbohydrate you should consume per day by following this formula:

1. Calculate your daily calorie needs by using an online calculator, such as this.
2. Multiply your total calories by the recommended carbohydrate percentage according to your recommended DNAFit Diet i.e. 40% (0.4) for Low Carbohydrate, 55% (0.55) for Mediterranean or Low Fat, or other plan you wish to follow.
3. This gives you the total amount of calories of carbohydrates you should consume per day. Divide this number by 4 (because carbohydrates contain 4 calories per gram) in order to get the amount in grams.
4. Remember, the higher your carbohydrate sensitivity, the greater proportion of fibrous carbohydrates you should consume as a total of your carbohydrate intake. 

For example, this is what it would look like for a 30 year old male who is 180cm tall and 99kg in weight, looking to lose 0.5kg per week, who has been recommended a DNAFit Low Carbohydrate Diet:

2,209 calories per day x 0.4 = 884 calories from carbohydrates

884 / 4 = 221 grams of carbohydrate per day.