Boston: Dieters have long believed that low carbohydrate consumption is critical to weight loss, but a study found that not all low-carb diets help with weight loss. Some foods even cause weight gain.

Researchers from Harvard studied data from more than 123,300 people from three different health databases.

In the study, participants ate one of five low-carbohydrate diets and had their body mass index (BMI) and weight loss measured every four years for more than 20 years.

The study found no significant difference in weight loss despite participants eating an overall low-carbohydrate diet (as long as they reduced their intake of meat, eggs, and dairy-based proteins). While some people also gained weight.

People who ate low-carbohydrate diets but continued to eat unhealthy carbs and animal protein gained weight during the study.

Over a four-year period, people who ate unhealthy foods gained an average of 0.90 kg. While a group of participants gained about 2.25 kg of weight was also observed.

Participants whose low-carbohydrate diets were based on plant-based foods and carbs from whole grains were observed to lose weight.

The study, published in the journal JAMA, found that participants whose diets consisted of healthy low-carbohydrate foods, plant-based proteins (such as pulses, peanuts and chickpeas) and healthy fats (such as fish, but also pears and eggs) They lost the most weight during the study period and maintained it.