One of the most popular dietary exclusions is gluten. Although originally it was used for Coeliac disease and those with a gluten sensitivity, people are now using a gluten-free diet for other health benefits.
But is a gluten-free diet helpful for weight loss and body composition for those who don’t have gluten issues?
There are many dietary approaches used to address metabolic syndrome and obesity – one being a gluten-free diet. By excluding foods that contain gluten, it’s theorised that would promote control of body weight, reduce fatty tissue and improve the parameters of metabolic syndrome.
However, this theory is still controversial, which led the researchers to design a systematic review. The goal of the study was to review the evidence around the effects of a gluten-free diet on body composition and metabolic syndrome.
Researchers conducted a literature search for studies until March 2021 without language restriction.
Studies were eligible if they were original studies with male and female adults without a diagnosis of Coeliac disease, participants undertook a gluten-free diet, and the results included the effects on weight loss and metabolic syndrome. All trials included were randomised clinical trials.
Although the initial research identified 3198 articles, only 4 studies were considered eligible after assessment. Researchers also conducted a risk of bias assessment on each study.
The clinical trials were conducted between 2017-2020, with the smallest sample size of 21 participants and the largest of 60 participants. Length varied from 6 weeks to 12 weeks. Two of the studies promoted a reduction of energy intake and one promoted a calorie-restricted high-protein diet.
In all studies, a gluten-free diet was not significantly associated with weight loss. In one study, fat-free mass was higher and insulin resistance improved in the gluten group (a high-protein calorie-restricted diet) compared to the gluten-free group.
In two studies, mean waist circumference was lower in participants on a gluten-free diet. There was also a reduction in body fat percentage of 2.3% and lower serum triglyceride levels.
The risk of bias varied between the studies, with only one study having low level risk of bias across the 5 areas assessed.
The researchers concluded that a gluten-free diet did not seem to promote weight loss in people who do not have Coeliac disease. However, it was associated with a lower waist circumference, body fat percentage and triglycerides.
They noted that for some individuals, a gluten-free diet rich in wholegrains can be a balanced, healthy diet strategy. But for those without gluten sensitivity or Coeliac disease, a gluten-free diet provided no additional nutritional benefit.
Some limitations of the study were noted. These included potential confounding factors and the lack of studies included that persisted longer than 12 weeks. They suggested that the improvements in body composition were encouraging, but that it could be due to an adherence to a generally healthy diet plan – one that involved caloric restriction, more fruit and vegetables and less consumption of sugary and fried foods.
Further studies and reviews are needed to support the research team’s findings and conclusions.
Orange, L.G., Andrade, M.I.S.D., Lima, C.R., Dourado, K.F., Santos, T.M., Petribu, M.M., Calaça, P.R.D.A. and Silva, S.A., 2022. Does a Gluten-free Diet Improve Metabolic Syndrome Parameters? A Systematic Review. International Journal of Cardiovascular Sciences, (AHEAD).