If you've ever tried out the latest diet fad only to find yourself gaining weight and feeling awful and wondered what you were doing wrong, scientists now have an explanation for you.
Israeli researchers, writing in the journal Cell this week, have found that different people's bodies respond to eating the same meal very differently — which means that a diet that may work wonders for your best friend may not have the same impact on you.
Lead authors Eran Segal and Eran Elinav of the Weizmann Institute of Science focused on one key component used in creating balanced diet plans like Atkins, Zone or South Beach. Known as the glycemic index or GI for short, it was developed decades ago as a measure of how certain foods impact blood sugar level and has been assumed to be a fixed number.
But it's not. It turns out that it varies widely depending on the individual.
The researchers recruited 800 healthy and pre-diabetic volunteers ages 18 to 70 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 had.
Each person was asked to eat a standardized breakfast that included things like bread each morning.
They found that age and body mass index, as expected, appeared to impact blood glucose level after meals, but so did something else. Different individuals showed vastly different responses to the same food, even though their own responses remained the same day to day.