An Israeli study says personalized nutrition is the way to reach your health and weight goals, according to a release posted on eurekalert.org.

The study tracked the blood sugar levels of 800 people for a week and the results suggest that even if everyone ate the same things, their bodies would process the foods differently and would produce different outcomes for each individual.

Years ago, a standard for ranking foods was developed based on the effect they had on blood sugar levels.  Called the glycemic index (GI), doctors and nutritionists use this index as tool to recommend healthy diets to patients.  The system was developed based on the average results of several studies, and is not exactly tailored to the individual in the group.

Study leaders, Eran Segal and Eran Elinav of the Weizmann Institute of Science in Israel, determined the GI for any food in a particular individual is not always a constant and depends upon the metabolism of the individual.

Analyzing a total of 46,898 meals, the researchers looked at things like body measurements, glucose monitoring, stool samples, and an app to report food intake and lifestyles of the participants. The volunteers in the study also received some standardized meals for their breakfast.

Not surprisingly, age and body mass index (BMI) were associated with glucose levels after eating, but the analysis also showed that there were significant differences in the body’s responses to the same foods when eaten by different people.  The individual’s response to eating the same food from one day to the next did not change.

Segal says we did not fully appreciate the differences in responses to foods from one person to the next, with some even having an opposite reaction, and that leaves a big gap in the understanding of how to recommend food guidelines for individuals.

The team adds that tailoring diets to the individual based on their own responses to food intake could allow physicians and nutritionists to control blood sugar levels and medical conditions associated with them.

They add that in some cases where it is thought that individuals are not being honest while trying to follow a recommended diet, the truth is that the recommendations could be at fault as well, in that what is considered healthy for some is not always the case.