Little Change in Diet After Onset of Type 2 Diabetes, Metabolic Syndrome, and Obesity in Middle-Aged Adults: 11-Year Follow-up Study.

Randomized controlled trials have established the beneficial effect of a healthy diet in the treatment of cardiometabolic disorders. Healthy diet recommendations are based on this evidence (1). However, limited evidence is available on whether individuals with these conditions actually follow such dietary recommendations in an effective way, that is, by making long-term changes in their dietary behavior.

In this cohort study of 4,703 participants (mean age 49.5 years, 27.8% women) from the Whitehall II study (www.ucl.ac.uk/whitehallII), we screened participants for type 2 diabetes (T2D), metabolic syndrome (MetS), and obesity and then followed changes in diet with follow-up surveys. Participants were informed that they had diabetes or were obese but were not informed if they had MetS, and no dietary advice was given. Both prevalent (in 1991/1993) and new-onset cases (occurrence between 1991/1993 and 2002/2004) of T2D (according to the World Health Organization criteria [2]), MetS (the National Cholesterol Education Program Adult Treatment Panel III criteria definition), and obesity (BMI ≥30 kg/m2) were considered, as described elsewhere (3). Changes in diet were determined using repeated measures of the Alternative Healthy Eating Index (AHEI) over an 11-year follow-up (from 1991/1993 to 2002/2004). Given the dietary intake data collected with a validated 127-item food-frequency questionnaire, AHEI was created by summing its nine component scores (fruits, vegetables, ratio of white to red meat, trans fat, ratio of polyunsaturated to saturated fat, total fiber, nuts and soy, alcohol consumption, and long-term multivitamin use). Improvement (from below to above median AHEI score) and deterioration (from above to below median AHEI score) in diet over the follow-up was determined based on median value of 50.5 points.

Figure 1 shows that after adjustment for age, sex, ethnicity, socioeconomic status, marital status, total energy intake, smoking, alcohol consumption, and physical activity, neither prevalent nor new-onset T2D, MetS, or obesity were associated with improvements in diet among participants with an unhealthy diet at baseline. Among participants with a healthy diet at baseline, the likelihood of deterioration in diet was higher in those with prevalent T2D and obesity and in those with new-onset MetS compared with those without.

Figure 1

Prevalent (A and C) and new-onset (B and D) metabolic disorders as predictors of an improved diet in participants with an unhealthy diet (A and B) and predictors of deterioration in diet in participants with a healthy diet (C and D). Odds ratio (95% CI) are adjusted for age, sex, ethnicity, socioeconomic status, marital status, total energy intake, smoking, alcohol consumption, and physical activity.

In conclusion, being alerted to the presence of diabetes or its risk factor obesity does not appear to change dietary behavior in an observational framework where no dietary advice was given. Similarly, no change in diet was observed in people with MetS. These results are concordant with studies showing no evidence of sustained change in other lifestyle factors, such as alcohol consumption and physical activity, in participants experiencing chronic diseases (4) and with studies reporting high rates of smoking after myocardial infarction (5). We have previously shown that good adherence in AHEI is related to an almost twofold higher odds of reversing MetS, suggesting that reversal of cardiometabolic risk factors via changes in behavior is possible (3). Given this and the substantial estimated cost of nonadherence to dietary guidelines to society, dietary consultation is warranted in participants with metabolic disorders, such as diabetes, MetS, or obesity. In addition, further research is needed to identify effective interventions to ensure patients’ adherence to dietary recommendations.