July’s Paper of the Month is from the Proceedings of the Nutrition Society and is entitled: ‘Current metabolic perspective on malnutrition in obesity: towards more subgroup-based nutritional approaches?’ by Ellen E. Blaak.
Most people associate malnutrition with thinness, however malnutrition may both be a cause, as well as a consequence, of being overweight or obese.
Driven by easy access to energy-dense foods and a sedentary lifestyle, obesity has become a major global health and socio-economic problem in the 21st century. Worldwide, the prevalence of obesity, which increases the risk of developing type 2 diabetes (T2D) and cardiovascular disease is increasing alarmingly. Many low and middle-income countries are currently facing a double burden of disease where infection and undernutrition may occur simultaneously with a rapid increase in overweight and obesity, particularly in urban settings.
General guidelines to a healthy diet and increased physical activity may be effective in the prevention of T2D and cardiometabolic complications. Nevertheless, in practice, long-term results are so far disappointing. It is increasingly clear that ‘one size does not fit all’ and that an individual or sub-group based approach may optimize intervention outcome.
The present review focusses on whether a personalised diet based on a person’s metabolism – the products of interactions among a variety of factors including lifestyle/environmental, gut microbial and genetic – or based on the composition of their gut bacteria (microbiota) may be effective to improve the success of nutritional intervention with respect to health.
A reduced action of the hormone insulin in our body (insulin resistance) linked to obesity, precedes the development of T2D and cardiometabolic diseases. There may be different types of insulin resistance: some people are more insulin resistant in their muscles, while others are more insulin resistant in their liver. In one type of insulin resistance, it can for instance be the case that a diet low in fat and high in fibre may be more beneficial, whilst people with another type of insulin resistance may benefit more by a somewhat higher fat diet with, in particular, the more healthy type of fat.
In addition, the composition of our gut bacteria (microbiota) may be of importance in determining what diet is best for us. Our gut microbiota ferment indigestible carbohydrates or dietary fibers (as in whole grain products, pulses and fruits), that are incompletely digested in the first part of our intestine. Individuals with a high risk for obesity and diabetes may have a different gut microbiota composition and may, for that reason, benefit from another diet than healthy individuals.
A diet based on existing guidelines for healthy nutrition may be a good diet for all. Nevertheless, these guidelines based on the reference person may not represent the optimal diet for all.
Overall, in order to be able to define more optimal diets for individuals, with or without predisposed chronic metabolic diseases, we need more research on how our metabolism responds to different diets in specific subgroups.
More personalised diets may lead to better health outcome and a higher motivation to adhere to a diet or lifestyle.