Is Calorie Labelling the Solution to Weight Management?

A calorie is not just a calorie

Last month the UK's department of Health and Social Care introduced a new regulation that requires businesses with 250 or more employees in the UK – including cafes, restaurants and takeaways – to display the calorie information of non-prepacked food and soft drinks prepared for customers, be that online or in-store.

The measure forms a part of the UK government’s wider strategy to tackle obesity and to ensure that people are making informed and healthy choices when it comes to eating food. With latest statistics suggesting that over two thirds of UK’s adult population now being overweight or obese, solving this problem is crucial. However, is calorie-labelling the answer to an issue as complex as obesity prevention and weight management?

On the surface, this solution tends to make sense - make people aware of the calories in their food choices and deter them from overeating. Except, weight management isn’t a simple math equation. The ‘calorie in, calorie out’ approach to weight loss – which this policy seems to be promoting – is antiquated. In fact, the way our bodies process calories vastly differ due to several variables, including: 

• Gut microbiome

Trillions of bacteria are located in our bodies, especially our intestines. Gut bacteria affect how food is digested in our bodies and thus affect our weight. Researchers have found that people who tend to be naturally thin have different types of organisms living inside them when compared to those who are obese – especially bacteria that are able to break down certain kinds of food and use more calories. Gut bacteria also produce certain chemicals that can help make us full. Evidently, obesity can hardly be reduced to an issue of caloric density - our bodies our different in visible and invisible ways.

A research study  found that people who ate 16 grams of prebiotics per day for two weeks had higher levels of hydrogen in their breath, which indicates higher levels of gut bacterial fermentation, less hunger, as well as higher levels of GLP-1 and PYY hormones, which make us feel more full and help avoid overeating. Calorie labels do not account for these nuances.

Foods that are good for our gut bacteria include whole grains, fruits and vegetables, nuts and seeds, polyphenol-rich foods like dark chocolate and green tea. Fermented food like yoghurt, kombucha, kefir and sauerkraut that contain beneficial bacteria like lactobacilli are also great for gut health. On the other hand, sugary foods, artificial sweeteners containing aspartame and saccharin, and saturated fat are damaging to our microbiome.

• Thermic Effect of Food (TEF)

Calorie labelling doesn’t account for the work the body must do to utilise it as fuel. Protein-rich foods, for example, have a higher thermic rate which means it costs our body more energy to digest and metabolise. So, while protein technically has 4 calories per gram, the body must spend 25% of those calories to convert it into usable fuel, so really it’s closer to 3 calories per gram. As such it disproportionately contributes to the feeling of fullness (satiety) after having consumed a meal. 

• Satiety

Satiety simply means the feeling of fullness and the loss of appetite after eating food. If the goal is to tackle the issue of over-eating in a healthy and sustainable way, closer attention needs to be paid to the kinds of food that contribute to prolonged satiety. There is a complex gut-brain connection through which our stomach signals the feeling of fullness to our brains. 

So, the amount of calories you need to consume to feel full from a croissant is not the same as a portion of boiled potato with the same caloric value. In fact the macronutrient composition of foods contribute hugely to the feeling of fullness. Several studies have shown that protein is the most filling macronutrient. It changes the level of several satiety hormones including ghrelin and glucagon-like peptide 1 (GLP-1). Fibre-rich food can also add volume and bulk to your meal and prolong the gastric emptying time, thus also prolonging the feeling of fullness. 

The processing of food hugely contributes to reducing satiety, as food structure influences how easily nutrients are absorbed and digested by our bodies. For example, in the case of whole nuts or carbohydrates that are still contained in whole plants, retain their higher fibre content and thus reduce the digestibility while slowing down the absorption of nutrients, thus contributing to satiety. This is the opposite of what happens when we consume processed carbohydrates and fats which can alter the molecular signals generated in the body that tell us when to stop eating by increasing the levels of hormones such as PYY - an appetite suppressant hormone secreted by the gut. As such, consuming processed foods - even if they’re supposedly low/moderate calories - can lead to unconscious and excess food consumption. 

• Diet composition

While it’s well known that not all calories are created equal, we still tend to be resistant to any food that is high in calories, because we assume it automatically equates to fat gain. Policies like calorie labelling only feed into this narrative. Having a more macro-nutrient driven approach to food choices means we can opt for high-quality, healthy foods like nuts, healthy fats, unrefined carbohydrates that although high in caloric density,  contribute to the overall feeling of satiety and help prevent unwanted weight gain and chronic disease. 

The bottom line is that a calorie is not just a calorie, and that a host of issues matter when it comes to weight management. Any policy that encourages people to choose food only based on caloric value ignores the complex issue that weight management is. There is no easy solution to this issue other than teaching people about the importance of ‘nutritional hygiene’, the medicinal properties of good food, the social aspects of enjoying a good home-cooked meal with friends and family, just to name a few examples. At the end, it is up to us to ditch the labels and instead strive for balance whilst being fully aware that healthy weight management doesn’t even begin with calories, let alone end there.