Nutritionists warn that 'zero' and 'light' labels can be misleading about health benefits

Experts caution that low-calorie ‘zero’ or ‘light’ claims often create false impressions of healthfulness, highlighting the need for consumers to scrutinise ingredient lists and overall nutritional content rather than rely solely on marketing labels.

Choosing a drink or snack labelled “zero” or “light” can feel like a simple way to improve the diet, but nutritionists say the maths does not always work that way. A report in Metrópoles warns that low-calorie claims can create a false impression of healthfulness, because calories measure energy only and say little about how nutritious a food really is.

Caroline Romeiro, a technical nutrition manager at Brazil’s Federal Council of Nutrition, said the calorie count alone does not reveal the quality of a food. She pointed to foods such as nuts and avocado, which are energy-dense but bring useful nutrients, and contrasted them with some “zero” drinks that may contain sweeteners, colours, flavourings and preservatives without adding much nutritional value. Giovanna Barreiro, a nutritionist at Hospital Brasília, said the issue is the overall composition, not just the number on the label.

The Metrópoles report also notes that many low-calorie products are ultra-processed, meaning they are manufactured with multiple additives to preserve taste, texture and shelf life. Romeiro said cutting calories does not automatically improve a product, because one ingredient is often removed while others are added to keep it appealing. Cynara Oliveira, a nutrition supervisor at Hospital Santa Lúcia, added that satiety depends on fibre, protein and the volume of the food, so a low-calorie choice may leave someone hungry again sooner.

For parents and carers trying to make healthier choices, the practical advice is to look beyond front-of-pack claims. Romeiro recommends checking the ingredient list, the order in which ingredients appear, and the amounts of added sugar, sodium, fats, fibre and protein. It is also worth comparing values per 100 grams or millilitres, as well as the number of servings in the package, rather than relying only on marketing terms such as “zero”, “light” or “low in calories”.