Carbohydrate Confusion: Separating Fact from Fiction

What are Carbohydrates?

Carbohydrates are one of the three main macronutrients in the diet — protein, fat and carbohydrate.

Carbohydrates are the main source of energy for the human body, and are necessary for a healthy and balanced diet. In the UK, the government recommend that up to half of our daily energy (calorie) intake comes from carbohydrates.

The three main types of carbohydrates are sugars, starches and fibre, all of which are digested in the body into glucose (sugar).

Most people in the UK eat too much sugar, which are referred to as free sugars.

Free sugars include:

Honey
Syrups
Unsweetened fruit juices
Vegetable juices
Smoothies
Sugar (i.e. brown sugar, caster sugar)

Starchy foods include bread, rice, pasta and potatoes. Opt for whole grain starchy foods such as whole grain bread, brown rice and wholemeal pasta, as these release their energy (sugar) more slowly than their refined counterparts (i.e. white bread).

Finally, fibre refers to the portion of plant-foods which cannot be digested in the small intestine. Instead, it’s digested in the large intestine by healthy gut bacteria, which has beneficial effects for our health.

High-fibre foods include:

Fruits and vegetables (with skin on)
Pulses
Legumes
Whole grain cereals
Nuts and seeds

The government recommend that we eat at least 30g of fibre per day, however, most people in the UK do not eat enough. High fibre diets reduce our risk of bowel cancer, cardiovascular disease and type 2 diabetes (1).

Carbohydrates Don’t Make us Fat

Despite popular belief, carbohydrates actually contain the least amount of calories per gram compared with other macronutrients (see below).

Calorie content of macronutrients (kcal/gram):

Protein = 4 kcal
Fat = 9 kcal
Alcohol = 7 kcal
Carbohydrate = 3.75 kcal

Whilst carbs themself are relatively low in calories, it’s worth thinking about what you’re putting on your carbs as the calories can quickly add up.

For example, a medium slice of wholegrain toast with a quarter of an avocado (40g) contains around 150 calories, whereas opting for an entire small avocado (120g) could provide as much as 350 calories.

As with anything, excessive portion sizes can lead to overconsumption of calories, which might result in weight gain.

Some of the healthiest areas of the world include Japan and the Mediterranean regions, where their diets are typically high in carbohydrate foods such as rice, pulses and legumes (2, 3).

Large scale studies have actually found that a diet which is rich in wholegrain carbohydrates such as oats, brown rice and wholegrain bread reduces your risk of type 2 diabetes, cardiovascular disease and cancers (4, 5).

What’s more, a randomised control trial, which was published this year, found that a whole grain-rich diet reduces body weight and systemic low-grade inflammation (6).

Low Carbohydrate Diets

Low carbohydrate diets lead to a small but significantly greater weight loss (about 2kg) compared with traditional low fat diets (7, 8).

Plus, low carb diets may increase metabolism, with one study demonstrating that low carb dieters burn 250 more calories per day than those on a higher carb diet (9). This could help people to avoid weight regain, which is common amongst dieters (10).

Low carb diets have also been shown to be effective in improving blood sugar control in diabetics as well as having favourable effects on cardiovascular risk factors (11, 12).

It would appear that consuming a low carbohydrate diet with less than 26% of total energy from carbohydrates (130g of carbohydrate per day) has the most beneficial effects on cardiovascular blood markers.

Very low carb diets such as the ketogenic diet usually contain 20-50g carbohydrate per day. This can lead to impressive weight loss results, but we need more research in humans to better understand the long-term effects of the ketogenic diet on our health.

A ketogenic diet is hard to follow due to its restrictive nature, plus you’re likely to miss out on the health benefits associated with whole grains and fibre. It requires careful planning and ideally supervision from a Registered Dietitian to ensure sufficient nutritional adequacy.

The secret to healthy weight loss is achieved with a Registered Dietitian – prescriptive high fibre diets that are naturally low in ‘net carbs’ are individually prescribed by myself to achieve sustainable fat loss.

There remains strong evidence to support the health benefits of a balanced and unprocessed diet which is rich in whole grains carbohydrates, pulses and legumes. As with any diet, the choice is yours.