Foods highest in carbohydrates: which ones and how much

What are carbohydrates, and what types are there?

Carbohydrates are the fuel the body can use most readily. Each gram provides around 4 kcal [2]. The European Food Safety Authority (EFSA) sets a reference intake of 45–60% of daily energy for adults and children aged one and over [3].

They are grouped into three types according to the size of their molecules.

• Sugars (monosaccharides and disaccharides). These are small molecules that are absorbed quickly, such as glucose, fructose in fruit, lactose in milk and sucrose (table sugar).
• Oligosaccharides. These are short chains, such as the fructans in wheat and onions and the galacto-oligosaccharides in pulses, which feed bacteria in the colon.
• Polysaccharides (complex carbohydrates). These are long chains, the main one being starch, the energy store in cereals, pulses and root vegetables. Fibre is also in this group, but the small intestine cannot digest it.

For normal bowel function, adults need 25 g of fibre a day [3]. Aim to get at least this amount from food, with carbohydrates coming mainly from wholegrains, vegetables, fruit and pulses [4].

Which foods are highest in carbohydrates?

The figures vary considerably between raw and cooked foods. Rice, pasta and pulses absorb water as they cook, so the amount per 100 g falls to less than half. These are approximate values from the Spanish Food Composition Database [1].

When comparing figures, always check whether they refer to raw or cooked food. 100 g of dried rice is not the same as 100 g of rice on your plate.

What is the difference between complex carbohydrates and sugars?

The difference lies in the molecule and, above all, in the food it comes with. The starch in wholegrains and pulses comes with fibre and protein. It is digested more gradually and keeps you feeling full for longer. Sugars are absorbed quickly, especially when consumed in a drink.

The World Health Organization distinguishes sugars in whole fruit, vegetables and milk, which it does not limit, from free sugars [5]. These are sugars added to foods and drinks, as well as those in honey, syrups and fruit juice [5]. It recommends that they provide no more than 10% of daily energy—about 50 g on a 2,000 kcal diet [5]. Reducing this to below 5% brings further benefits, particularly for dental health [5].

How fibre and cooking affect carbohydrates

Fibre affects how carbohydrates behave in the body. Soluble fibre, found in oats and pulses, forms a gel-like substance that slows stomach emptying. Insoluble fibre, found in bran and fruit and vegetable skins, adds bulk to stools and helps food move through the gut.

The speed at which a food raises blood glucose is measured by its glycaemic index, which compares it with pure glucose. In practice, though, we rarely eat foods on their own. Pairing rice or potatoes with vegetables, extra virgin olive oil and a source of protein (such as eggs, fish or pulses) slows the absorption of the meal as a whole.

Cooking matters too. Al dente pasta is digested more slowly than pasta cooked until very soft. And if you chill cooked potatoes or rice in the fridge, some of their starch becomes resistant starch. This portion is not absorbed in the small intestine and can be used by the gut microbiota in the colon.

Do carbohydrates cause weight gain?

No single food or nutrient causes weight gain or loss on its own. Body fat increases when, over time, you take in more energy than you use, whether that energy comes from carbohydrates, fat or protein.

Ultra-processed foods made with refined flour, added sugars and fats pack a lot of energy into a small volume and are not very filling. This can make it easy to eat more than you realise. Pulses, steamed potatoes, oats and fresh fruit, by contrast, provide bulk, water and fibre.

In a well-planned approach to weight loss, complex carbohydrates help you keep up your energy day to day and during strength training. They also prevent the intense hunger that appears when intake is restricted too much. If you want to reduce your calorie intake, adjust portions to your energy needs and choose good sources, without cutting out whole food groups. For ideas on putting meals together from breakfast to dinner, see our guide to losing weight without regaining it.

What counts as a portion of carbohydrate?

Diabetes nutrition education uses a carbohydrate portion to mean an amount of food that provides 10 g of carbohydrate [6]. Even if you do not have diabetes, it can help you picture portion sizes.

Using the figures in the table, here are some approximate equivalents [1].

• 1 portion (10 g of carbohydrate). 200 ml of milk or plain yoghurt, 50 g of boiled potato, 50 g of banana, 100 g of apple, or 15 g of uncooked rice or pasta [1].
• 2 portions (20 g of carbohydrate). 40 g of white or wholemeal bread, 100 g of boiled potato, 70 g of cooked rice or pasta, or 120 g of cooked pulses [1].

For a balanced main meal, use the plate method: half a plate of vegetables, a quarter of protein-rich foods and a quarter of carbohydrate-rich foods, preferably wholegrain. Include pulses at least four times a week, as recommended by the Spanish Agency for Food Safety and Nutrition [7].

Common mistakes with carbohydrates we see in consultations

Cutting out bread, rice and pasta all at once. It is often the first change people make on their own before coming to see us. It usually does not last long, because tiredness and mid-afternoon hunger set in.

Comparing raw and cooked figures. “Pasta has 71 g of carbohydrate; that’s a lot.” That figure is for dried pasta. Once cooked, it contains about 27 g per 100 g [1].

Counting whole fruit as if it were sugar. Whole fruit does not count towards the limit on free sugars [5]. Juice does, and it is much less filling.

Having no carbohydrates at dinner for fear they cause weight gain overnight. What matters is what you eat over the whole day. A dinner with some potato, rice or wholemeal bread is usually more satisfying.

If carbohydrates do not agree with you

Some short-chain carbohydrates are not fully absorbed in the small intestine and are quickly fermented by bacteria in the colon. They are known as FODMAPs, an abbreviation of fermentable oligosaccharides, disaccharides, monosaccharides and polyols. They include fructans in wheat and onions, galacto-oligosaccharides in pulses, lactose, and polyols such as sorbitol and xylitol.

If your gut is more sensitive to gas and distension, these foods may cause bloating, wind and pain. If this happens often, do not cut foods out on your own. Speak to your doctor first to rule out other causes; afterwards, a dietitian-nutritionist can help you work out which foods you tolerate. Many of these carbohydrates feed the gut microbiota, and avoiding them unnecessarily for a long time can reduce its diversity.