Along with protein and fats, carbohydrates are a type of macronutrient.

In days gone by, fats got the blame for making us gain weight. But, in recent years, and particularly with the rise in popularity of the keto diet, the blame has shifted towards carbs.

Much like with fats, however, this reputation is undeserved.

Carbohydrates can – and should – be part of a healthy, balanced diet or weight loss plan.

When you eat carbs your body breaks them down into glucose. Glucose, or blood sugar, is the main source of energy for your body’s cells, tissues, and organs (including your brain).

So, if carbs are so useful, why are they so controversial?

Not all carbs are created equal

Once in your body, the sugar that’s found in a piece of fruit is broken down into the exact same sugar found in a chocolate bar.

What makes them so different is the rate at which that sugar enters the bloodstream.

Refined or highly-processed foods like sweets, cookies, cereal, and ice cream are digested extremely quickly and cause a ‘spike’ in blood sugar that is usually followed by a ‘crash’.

On the other hand, whole foods such as vegetables, beans, rice, and oats are broken down more slowly and therefore result in a steadier release of sugar into the bloodstream.

Why blood sugar matters for weight loss

do carbs make you fat

We feel our best when our blood sugar is balanced; not too high and not too low.

When blood sugar crashes, you are more likely to experience hunger and cravings that lead to poor food choices.

In a 2021 study of more than 1000 people, researchers found that large dips in blood sugar resulted in a 9% increase in hunger.

That might not sound like a lot, but this translated to around 312 more calories being consumed over the course of the day.

Over the course of a year, that could potentially turn into 20 pounds of weight gain.

In addition to keeping hunger and cravings under control, balanced blood sugar helps keep our brain healthy, our energy levels stable and our mood balanced. Symptoms of being on the ‘blood sugar roller coaster’ include irritability, poor sleep, brain fog, anxiety.

How to maintain stable blood sugar

The glycaemic index (GI) rates carbohydrates according to how quickly they raise the glucose level of the blood.

GI can give us a good idea of which foods to choose to maintain stable blood sugar levels, but more useful still is Glycaemic Load (GL).

GL is a measure that takes into account both the amount of carbohydrate in a portion of food together with how quickly it raises blood glucose levels.

It is calculated by multiplying the grams of available carbohydrate in the food by the food’s GI, and then dividing by 100.

High GL foods include:

  • Crisps
  • Sweets
  • Cakes
  • Soda/fizzy drinks
  • Cereal

Low GL foods include:

  • Fruits such as pears, berries, and oranges
  • Vegetables such as carrots, cabbage, and peas
  • Pulses such as lentils and chickpeas
  • Grains such as quinoa and pearl barley
  • Rolled oats

Generally, the more processed and refined the food is, the higher its GI and GL.

Carbs are not ‘good’ or ‘bad’

It would be easy at this point to label high GL carbs as ‘bad’, and low GL carbs as ‘good’.

But the truth is that both can play a part in your diet.

Yes, highly processed or refined carbs will lead to blood sugar highs and lows but, as long as you mostly consume ‘whole’ sources of carbohydrates like fruits and vegetables, you can control your appetite and mood, reduce cravings, and provide your body with energy throughout the day.


1. Photo by Geraud Pfeiffer from Pexels