Many 'healthy snacks' are high in calories

It is the time of year when research about diet and exercise makes a big splash in the headlines, but today the Daily Mail warned that dieters should steer clear of seemingly healthy dips and spreads that are actually high in calories.

The newspaper highlighted warnings that hummus, which is widely thought to be healthy, has a surprisingly high calorie content. Despite its high fat and energy content, a recent survey of Britons showed that two-thirds of people underestimate the number of calories in the chickpea dip. The survey was commissioned by the World Cancer Research Fund (WCRF), which says that people can still be confused about the calorie content of everyday foods, which can affect weight and therefore cancer risk.

The WCRF says that the situation is not helped by the application of labels such as ‘light’ and ‘reduced fat’ to foods that actually have a high calorie content and that may still cause weight gain if consumed regularly. In particular, the WCRF says the public should be aware of the ‘energy density’ of foods such as mayonnaise or hummus, which have a high number of calories in a small portion.

What does the WCRF say?

The WCRF reported the results of the calorie survey, saying that it found that about two-thirds of UK adults underestimated the number of calories in foods such as hummus (only 32% selected this as high in calories) and ‘light’ mayonnaise (only 29% selected this as high in calories). They say this is a concern because being overweight is a factor in a number of diseases, including cancer, heart disease and diabetes.

They also add that if people are unaware which foods contain a lot of calories then it makes it even more difficult for them to adopt a diet that can maintain a healthy weight. One of the WCRF’s 10 recommendations for cancer prevention is to avoid sugary drinks and energy-dense foods. They say that this is because they can lead to weight gain and there is strong evidence that excess body fat increases the risk of six types of cancer, including bowel cancer and breast cancer.

The WCRF has produced a leaflet entitled “Energy density: finding the balance for cancer prevention”. The leaflet explains how energy-dense a food is, and how choosing foods with a lower energy density can help maintain a healthy weight.

What is an 'energy-dense food'?

The WCRF defines the energy density of foods as high, medium and low:

• High energy density foods contain more than 225-275kcal per 100g. They include fast foods, cakes, biscuits, crisps, confectionery, butter and other spreads.
• Medium energy density foods contain around 100-225kcal per 100g. They include foods such as bread, lean meat, poultry and fish.
• Low energy density foods contain less than about 60-150kcal per 100g. Most vegetables and fruits would be in this group.

The WCRF says that the main influences on a food’s energy density are its water and fat content. Foods that have more water tend to be bulkier and give you “more bites for fewer calories”. Low energy density foods also tend to have more fibre, which can help you feel fuller for longer.

How can I tell what an energy-dense food is?

Many foods include nutritional data on their labels, usually telling you the number of calories per portion or per 100g. You can compare these values to the WCRF’s energy values listed above. You might also find it helpful to look at specific aspects such as the fat content of a food, as explained in our article on how to read food labels.

The WCRF has also produced an online energy density calculator for food that allows you to click on a type of food and find out which energy density range it falls under. This may be useful for products such as loose fruit and vegetables that do not come with packaging. It is also possible to input the number of calories per 100g found in packaged foods to see their ranking.

Does weight affect cancer risk?

There are many different factors that contribute to risk of cancer, such as age, the day-to-day environment and genetic make-up, but cancer experts suggest that maintaining a healthy weight can lower the risk of developing cancer. Cancer Research UK says that experts estimate that “maintaining a healthy bodyweight, making changes to our diet and taking regular physical activity could prevent about one in three deaths from cancer in the UK”.

The cancer charity says that overweight or obese people have an increased risk of bowel cancer and pancreatic cancer and that obesity (having a body mass index of 30 or more) is associated with an increased risk of oesophageal cancer, kidney cancer and gallbladder cancer. In women, being obese is associated with an increased risk of breast cancer (in post-menopausal women) or womb cancer.