Ultra-processed foods

Ultra-processed foods have been described as ‘formulations mostly of cheap industrial sources of dietary energy and nutrients plus additives, using a series of processes’, and containing minimal whole foods.¹ They are often inexpensive, have a long shelf-life, and are considered convenient if they are either ready-to-eat or ready-to-heat.

The Nova classification system has four categories:²

1. Unprocessed or minimally processed foods

2. Processed culinary ingredients

3. Processed foods

4. Ultra-processed foods.

In a controlled trial by Hall et al, participants were randomised to either an ultra-processed or unprocessed diet for two weeks in a crossover design, where all food was supplied for a four-week period.3 Meals in both diets were matched for calories, energy density, macronutrients, sugar, sodium, and fibre. Subjects were instructed to consume as much or as little as they wished. When consuming the ultra-processed diet, energy intake was greater, with increased consumption of carbohydrate but not protein.

Energy intake correlated with weight changes
(p equals less than 0.0001). Participants gained 0.9 SD 0.3 kg (p equals 0.009) during the ultra-processed diet, and lost 0.9±0.3 kg (p equals 0.007) during the unprocessed diet. The authors concluded that ‘limiting consumption of ultra-processed foods may be an effective strategy for obesity prevention and treatment’.²

Increasingly, questions are being asked about whether, and to what extent, ultra-processed foods should be included in a diet in someone aiming to eat well. More research is needed to analyse the impact on a person’s health status, beyond the consideration of appetite and weight gain.