Eating a diet low in ultra-processed foods (UPFs) and exercising can cut the risk of type 2 diabetes, even in those with a strong genetic disposition to the condition, new research being presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2) suggests.
The analysis of data on tens of thousands of people in the UK found that those who had a diet low in processed food and did regular moderate to vigorous physical activity were up to 70% less likely to develop the condition.
In those with a strong genetic predisposition, the diet-exercise combination halved the risk of type 2 diabetes.
"Type 2 diabetes is caused by a combination of a person's genetic susceptibility and their lifestyle," says Wenxin Xu, of City University of Hong Kong, Hong Kong, China, who led the research.
"In terms of lifestyle, eating more ultra-processed food is associated with a higher risk, whereas physical activity is protective.
"However, whether a lower UPF intake reduces genetic susceptibility hasn't been clear. Nor have we known whether exercising helps offset the impact of UPFs.
"It is important to find this out because, unlike genetic susceptibility, diet and physical activity can be modified – they are things people can change."
To find out more, Ms Xu and colleagues at the City University of Hong Kong (Hong Kong and Dongguan) examined data on 56,964 adults in the UK Biobank study (average age 69.5 years, 42.3% male).
Detailed questionnaires provided information on UPF intake at baseline, as defined by the Nova system1. The amount of moderate-to-vigorous physical activity (MVPA) was calculated from activity trackers worn on the wrist for a week. MVPA is exercise that increases heart rate and breathing rate. Examples include brisk walking, cycling, hiking and walking the dog. Sports, housework and gardening jobs that require sustained physical effort are also included. Genetic susceptibility to type 2 diabetes was estimated from genetic data.
During an average follow-up period of 7.8 years, 926 of the participants developed type 2 diabetes.
As expected, eating more UPFs was associated with a higher risk of the condition and, MVPA, a lower risk. Type 2 diabetes risk increased in line with UPF intake. Every 10% (by weight) of an individual's diet that was made up of UPFs increased their risk of type 2 diabetes by 7%. Meanwhile, the participants who met the World Health Organization (WHO) recommendation of at least 150 minutes of MVPA a week were 39% less likely to develop type 2 diabetes than those who exercised less.
Further analysis indicated that a lower UPF intake and MVPA both partially offset genetic susceptibility to type 2 diabetes.
In those whose genes put them at high risk of type 2 diabetes, a low UPF intake (approximately 11% or less of total food intake by weight came from ultra-processed foods) was associated with a 35% lower likelihood of the condition. Meeting the MVPA recommendations was associated with a 33% lower risk of type 2 diabetes.
The researchers also found that exercise seems to reduce the impact of UPFs, even in those with a strong genetic predisposition to type 2 diabetes. In participants with high UPF intake (approximately 33% or more of total food intake by weight came from ultra-processed foods), meeting WHO recommendations for MVPA was associated with 31% lower risk of type 2 diabetes risk in those with a high genetic risk, 57% in those with an intermediate genetic risk and 58% in those at low genetic risk.
The combination of lower UPF intake and MVPA was associated with even greater protection against the condition. It was linked to a 49% reduction of risk of type 2 diabetes in those whose genes made them highly susceptible to type 2 diabetes, a 70% reduction in those with an intermediate genetic susceptibility and a 59% reduction in those with a low genetic susceptibility.
This highlights the importance of considering lifestyle changes together, rather than in isolation, say the authors. They acknowledge that the findings are observational and so cannot prove cause and effect. However, they are in line with existing advice to eat a healthier diet and stay physically active to prevent or delay the onset of type 2 diabetes.
Ms Xu adds: "Our study indicates that our genes are not our destiny.
"Even among people with a high genetic susceptibility to type 2 diabetes, lower intake of ultra-processed foods and regular moderate-to-vigorous physical activity were associated with a substantially lower risk of developing the condition.
"While we cannot say that type 2 diabetes can always be avoided, our results suggest that healthy lifestyle choices may help reduce the risk whatever your genetic background."
