Why One Diet May Not Fit All

Blood sugar response to various foods may vary among different patients

(RxWiki News) Did you ever wonder why certain diets work for some people but not for others? Science might have just found the answer.

A new study from Israel found that the glycemic index (GI) of a given food may not be a set value — but may rather depend on the person consuming it. In other words, even if everyone eats the same meal, how that meal metabolizes may differ from person to person.

GI is a tool used to measure the effects of food on blood sugar levels. Doctors and nutritionists often use GI to develop healthy diets for patients. However, this finding suggests that personalized nutrition may be more beneficial for lowering blood sugar levels than the traditional GI-based method.

For this study, a team of researchers led by Eran Elinav, MD, PhD, a professor of immunology at the Weizmann Institute of Science in Israel, looked at the postprandial glycemic responses (PPGRs) of 800 prediabetic adults over the course of 46,898 meals. A PPGR is the amount by which blood sugar levels increase after a person eats a meal.

These researchers collected data on food intake, lifestyle, medical background and body mass index (BMI). A series of blood tests and a stool sample were also collected.

Patients were then connected to a continuous glucose monitor (CGM) for seven days. During this period, the first meal of each day was a standardized and given to all patients. Other than that, these patients ate their normal diets.

A high variability in PPGRs was found across patients who consumed the same meals. In other words, different patients had vastly different metabolic responses to the exact same foods.

From these results, Dr. Elinav and team developed an equation based on personal characteristics — such as BMI and gut bacteria — which could be used to predict a patient's metabolic response to a given meal.

In a small crossover study, these researchers found that tailoring meals based on this equation may effectively lower patients' PPGRs.

This study was published Nov. 19 in the journal Cell.

Information on funding sources and conflicts of interest was not available at the time of publication.

Review Date: 
November 23, 2015