Science now has an explanation for why many of us try out the latest diet only to find that it is not working. A study published in the journal Cell this week, has demonstrated that different people’s bodies respond to eating the same meal very differently – which means that a diet that may work wonders for one person may not have the same impact on another. A key component used in creating balanced diet plans like Atkins, Zone or South Beach called the glycemic index, developed decades ago as a measure of how certain foods impact blood sugar level, was assumed to be a fixed number. But it’s not. It turns out that it varies widely depending on the individual.
The researchers studied 800 volunteers and collected data through health questionnaires, body measurements, blood tests, glucose monitoring and stool samples. They also had the participants input lifestyle and food intake information into a mobile app that ended up collecting information on a total of 46,898 meals. They found that not only does age and body mass index impact blood glucose level after meals but that different individuals showed vastly different response to the same food even though their own responses remained the same day to day.
The Beginnings of Personalized Dieting and Nutrition
The researchers said these findings show that tailoring meal plans to individuals’ biology may be the future of dieting and that the study yielded many surprises for individuals. For example, a middle-aged woman in the study tried and failed many diets. Tests revealed that her blood sugar levels spiked after eating tomatoes – indicating it is a poor diet choice for her since blood sugar has been associated with cardiovascular problems, obesity and diabetes – but since she didn’t know this, she was eating them as part of her healthy diet plans several times a week.
The authors collected extensive phenotypic data from these individuals, which were then used to train a machine-learning algorithm that could accurately predict glycemic response to various meals. This study is an important proof-of-principle for the utility of tailoring nutritional and/or pharmaceutical interventions to each individual. Precise predictions of glycemic response could represent a powerful tool to optimize dosing of insulin (or dietary interventions) in type 1 or even type 2 diabetics to avoid hypoglycemic episodes and more. According to the lead author, the work “really enlightened us on how inaccurate we all were about one of the most basic concepts of our existence, which is how we eat and how we integrate nutrition into our daily life.”