The new research, published in The FASEB Journal, analysed how healthy genetically identical twins of differing body weights reacted to a fast food meal by measuring the effect on blood metabolites.
Led by Matej Oresic from the Steno Diabetes Center in Gentofte, Denmark, the team found that post-meal (postprandial) levels of circulating metabolites in the blood of the identical twins tended to be similar after the fast food meal, independent of weight differences.
The finding suggests that post-meal levels of metabolites linked to the risk of diabetes are dictated by what we eat and not just how much we eat, and that differences in genetics and the make-up of our intestinal microbiota are they drivers of type 2 diabetes.
“We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity,” reported the team. “Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially,” they added.
Oresic added that the study contributes to a better understanding of the genetic and environmental factors influencing several risk factors which are associated with obesity and metabolic disease like type 2 diabetes.
"When someone is overweight and at risk for diabetes, the conventional wisdom is to say 'lose weight,'" commented Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal, "and to a degree that recommendation holds true.”
“This report, however, shows that a calorie is not just a calorie as some would contend. Exactly what we eat and drink, and not just the number of calories, may be the most important factor in our health."
Genetically identical, but different weights, healthy young adults from a national (Finnish) study of twins were recruited to the study. After baseline tests – including measures of gut microbes from fecal samples – the twins were given a fast food meal, before being monitored and having blood samples taken over several hours.
The team analysed the effect of the meal on a broad panel of blood metabolites including amino acids, fatty acids and bile acids – comparing any differenced to differences in body weight or microbiota make-up.
Oresic and his colleagues reported that circulating metabolites, including those related to type 2 diabetes, were found in both individuals at the same levels – suggesting that the onset of this type of diabetes is largely influenced by genetic factors and/or the composition of gut microbiota, rather than body weight.
Indeed, the team noted that branched chain amino acids, known risk factors of diabetes, were increased in heavier as compared to leaner co-twins in the fasting state, but revealed that levels converged postprandially.
“This study also demonstrated that specific bacterial groups were associated with postprandial changes of specific metabolites,” said the team.