A recently completed obesity study spanning 20 years on the impact of diet quality in adulthood suggests that maintaining a high-quality diet at an older age can help stave off metabolic problems.
The longitudinal study was undertaken by researchers from the University of Hawaii Cancer Center, the University of Southern California Department of Preventive Medicine and the University of California Department of Radiology and Biomedical Imaging.
The results of the 2,000-participant multiethnic cohort study were published in Obesity Society.
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At the outset of the study, participants aged 45 to 75 were chosen. Researchers excluded any potential participants with BMIs (Body Mass Index) dramatically outside of the optimal range, smokers and those suffering from health conditions or taking medication that could impact their adiposity levels.
The participants were required to complete questionnaires on their daily food habits based on popular dietary indices. This involved providing researchers with information on their daily consumption of foods and drinks including fruits, vegetables unrefined grains as well as empty calories and alcohol.
They were also asked to provide details on their levels of physical activity. Four dietary indices were used including the Healthy Eating Index, the Alternative Healthy Eating Index, the alternate Mediterranean Diet score, and the Dietary Approaches to Stop Hypertension (DASH).
Participants were required to undergo whole-body dual-energy x-ray absorptiometry and abdominal magnetic resonance imaging scans to get an accurate estimation of their visceral adiposity levels and non-alcoholic fatty liver.
The accumulation of fat in visceral adipose tissue and the presence of non-alcoholic fatty liver were targeted as these qualities have been proven to create negative metabolic consequences in the human body, creating inflammation and cardiovascular problems.
It was discovered at the study’s conclusion that participants with better diet quality measures over the study period had lower adiposity levels, suggesting that a strong association between diet quality and the development of visceral adipose tissue and non-alcoholic fatty liver.
In particular, the Mediterranean diet was found to be inversely associated with excess body weight and a higher than optimal waist circumference.
Due to the 20-year span of the study, its frequent dietary assessments, the ethnic diversity of the participants and the advanced technology used to assess fat levels, researchers are confident in the validity of their findings.
They caution, however, that further ethnic-specific analyses are required among minority groups such as Native Hawaiians, Japanese Americans, and Latinos.
While findings attesting to the health benefits of the Mediterranean diet aren’t new, this is the first time a study has identified a strong inverse association with measures of abdominal and liver fatness after total body fat is taken into account and it suggests that looking at body fat distribution beyond BMI might be more useful when advising people on the impact of their diets.