NEW DELHI: Following a healthy diet to lose weight? Make sure it's minimally processed, suggests a study, which showed that reducing processing could help to sustain a healthy weight.

In a first, researchers from the University College London (UCL) nutritionally matched minimally processed (MPF) and ultra-processed (UPF) diets.

The results, published in the journal Nature Medicine, showed that participants lost twice as much weight eating minimally processed foods compared to ultra-processed foods.

“The primary outcome of the trial was to assess percentage changes in weight, and on both diets, we saw a significant reduction, but the effect was nearly double on the minimally processed diet,” said Dr Samuel Dicken, first author of the study from the UCL Centre for Obesity Research.

The trial split 55 adults into two groups. One group started with an eight-week diet of MPF, such as overnight oats or homemade spaghetti Bolognese.

After a four-week ‘washout’ period during which participants went back to their normal diet, they switched to a diet of UPF, such as breakfast oat bars or a lasagne ready meal. The other group completed the diets in the opposite order. In total, 50 participants completed at least one diet.

After eight weeks on each diet, both groups lost weight, likely as a result of the improved nutritional profile of what they were eating compared to their normal diet. However, this effect was higher (2.06 per cent reduction) on the MPF diet compared to the UPF diet (1.05 per cent reduction).

The greater weight loss experienced on the MPF diet came from reductions in fat mass and total body water, with no change in muscle or fat-free mass, indicating a healthier body composition overall, explained the researchers.

Further, there were also significantly greater improvements in the number of cravings and ability to resist them (craving control).

On the MPF diet compared to the UPF diet, participants reported a two-fold greater improvement in overall craving control, a four-fold greater improvement in craving control for savoury food, and an almost two-fold greater improvement in resisting whichever food they most craved.

The study "underlines the need to shift the policy focus away from individual responsibility and on to the environmental drivers of obesity, such as the influence of multinational food companies in shaping unhealthy food environments", said Professor Chris van Tulleken, from UCL Division of Infection and Immunity.