Do Carbs Make Me Fat?

Carbs seem to be high on the list of nutrients we love to hate!

We have all heard the phrase ‘No carbs before Marbs’, the belief that carbs make us fat is so long held, this has become a normal part of our vocabulary.

So many feel that they must avoid carbs to avoid weight gain and are now fearful of a sandwich at lunchtime- bread seems to be suspect #1 for many- I often hear someone say they are being ‘naughty’ today because they chose the sandwich for lunch.

So is it really true that carbs make you fat, where has this stemmed from and what are you missing out on if you remove carbohydrates from your diet?

What are Carbohydrates?

Carbohydrates are single molecules of sugar or chains of sugars. The longer the chain the more ‘complex’ the carbohydrate and therefore the longer it will take to break the carbohydrate down and use this energy in the body.

They are one of the three macronutrients (the others are fat and protein) and this means we need to eat them everyday in relatively large amounts, as compared with micronutrients (vitamins and minerals), which we need in much smaller quantities.

Carbohydrates can be:

  • Simple sugars (e.g. table sugar, sweets, sugary drinks, honey)
  • Starches (e.g. potatoes, pasta, bread, rice, grains)
  • Fibre (e.g. in fruit, vegetables and wholegrains)

Why Do We Need Carbohydrates?

Carbohydrates main function is to provide the body with energy and they are the bodies preferred source of energy to fuel our brain, muscles and organs as they break down into sugar more easily than fats or proteins which need to be converted.

The carbohydrate foods that also contain fibre are important to include in our diet everyday as fibre is important to health in many ways, including supporting gut health, being protective against diseases such as Type 2 Diabetes and certain cancers as well as keeping us fuller for longer after we eat a meal.

Certain carbohydrate foods like wholegrain bread, pasta or cereals also provide B vitamins, which are involved in many metabolic functions in the body and need to be consumed regularly as we don’t store these vitamins in the body.

How much carbohydrates do I need?

The Eatwell guide shows us to aim for around 1/3 or your daily energy to come from starchy foods and 1/3 from fruits and vegetables, so this means over 1/2 of your daily energy should come from carbohydrate foods.

Why do People say Carbs make you fat?

For those that like sciency stuff, the belief that carbohydrates are uniquely fattening comes from a theory called the carbohydrate-insulin hypothesis- this suggested that carbohydrates drive weight gain because they cause the release of the hormone insulin (which manages blood sugars in the body) and insulin causes a signal to the body to store more fat and therefore a conclusion was made that they are fattening (I have seriously simplified this, but nevertheless, be reassured that this theory does not hold true in science as this is a short term response after you eat, not to do with longer term fat storage).

This theory has been tested in research studies and it turns out that in fact, it doesn’t impact weight loss if you reduce the carbohydrates in people’s diets (and therefore the insulin levels) when people are eating the same amount of calories- i.e. it is about how much energy you eat, not the particular nutrient that it comes from. If it was the carbohydrates themselves causing the weight gain, then low carb diets would be the solution to everyone’s weight problem.

It has been shown that a low fat or low carb diet has similar results in weight loss but there are some studies that show there may be less likelihood of adherence to the low carb diet and therefore there may be more risk of weight regain in the long term.

If you overeat on any food then you can put weight on- there is nothing about carbohydrates that is any different. In fact carbohydrates contain around 4 calories(Kcals)/g, whereas fat contains around 9Kcals/g and Alcohol around 7Kcals/g, so if anything they are less likely to cause weight gain if eaten in the right quantities than fat- that’s not to demonise fat, but just to make the point that there is no reason to consider carbs to be a problem food when it comes to our weight.

Often we add fats to carbohydrates e.g. butter to bread, cream to mash, oil to chips and then we blame the carb for the weight gain we may experience. If you are wanting to lose weight or improve your health then considering cooking methods of your carbohydrates may be more beneficial than cutting them out altogether.

Can I Eat Sugar?

Sugar is found in many foods from sweets, chocolate, honey, syrups and drinks and is also naturally found in fruits and dairy foods. If we over consume sugar then this is undoubtedly bad for our physical and dental health. However, it is never healthy to label foods as ‘good’ or ‘bad’ and so enjoying foods containing sugar is fine, if we just consider how much of these we can have and still be healthy- there is certainly no need to completely eliminate sugar. If you feel addicted or out of control to sugary foods, then you may need support with your relationship with foods as we technically can’t be addicted to foods- it’s generally more about why we feel reliant on these foods that is important to understand.

Sugar in fruit and dairy is classed as natural sugar and we can eat this more readily than added sugars and of course these foods contain many other beneficial nutrients.

What happens when I don’t eat enough Carbohydrates?

By not including adequate carbohydrates in your day you may find:

  • You are lacking in energy
  • You have brain fog/headaches
  • You are grumpy/lower in mood
  • You are craving foods (especially carbs)
  • You are low in fibre (may lead to constipation and fibre is important for heart and gut health)
  • You overeat when you do eat carbs or on other foods

If you are regularly under consuming carbohydrates this means your body will have to use less efficient sources of fuel, this could be breaking down muscle to use proteins for fuel, or converting fats to ketone bodies- this is the bodies plan B for survival when it is starved, but is now marketed as a weight loss plan via the ‘Keto Diet’.

Long term restriction of carbohydrates can lead to under-fueling, and may cause disruptions to system functioning and female hormone production, which are particularly sensitive to energy and carbohydrate intakes.

Take Home Message

We are all different and depending on your activity levels, age, lifestyle etc., you may need more or less carbs than someone else in order to feel good and be healthy. If you are restricting carbohydrates just check in why, and if it is through fear of weight gain, then this may suggest you have some difficulties with your relationship with food and you may need support with that.

So, we can have carbs before Marbs and in fact it is healthy to eat them everyday, several times a day. Whole grains and other starchy carbohydrates are great options for regular consumption , but balance is key so don’t worry about including all types of carbohydrates as part of a healthy diet.