Almost one in five adults in the U.S. said they ate a “special diet” from 2015 to 2018, National Health and Nutrition Examination Survey (NHANES) data showed.
Among adults ages 20 and older, 17.1% reported that they stuck to a special diet on any given day, according to Bryan Stierman, MD, MPH, of the National Center for Health Statistics (NCHS) in Hyattsville, Maryland, and colleagues.
This percentage is substantially bigger than in previous years: 14.3% of U.S. adults followed any special type of diet in 2007 to 2008.
“About one-half of U.S. adults have diet-related chronic diseases, such as cardiovascular disease, high blood pressure, or type 2 diabetes,” the researchers wrote. “Special diets are one way that many adults prevent, treat, and manage such diseases.”
The study, published as an NCHS Data Brief, also pinpointed a low-calorie or weight-loss oriented diet as the most popular choice of diet, used by nearly 10% of all adults. Next was a diabetic diet, followed by 2.3% of adults on any given day, followed by low-carbohydrate (2%) and low-fat or low-cholesterol diets (1.8%).
Stierman’s group drew upon data from the cross-sectional NHANES. Dietary information was obtained via 23-hour dietary recall interviews with trained interviewers. “Special diets” were considered to be an affirmative response to the question: “Are you currently on any kind of diet, either to lose weight or for some other health-related reason?”
There was some variance of diet popularity according to age group, but a weight loss or low-calorie diet was overwhelmingly the favorite across every age group, Stierman and co-authors reported.
Diabetic diets were nearly twice as popular among those age 60 and over, used by about 4.7% of these adults. A low-sodium diet was another of the most popular diets among this older group (3%). Overall, more adults in this age group used any type of special diet compared with any other age group.
Interestingly, a “weight gain” diet was followed by 0.7% of those between the ages of 20 and 39, but not by any of the other age groups.
By 2017-2018, the popularity of weight loss and low-carb diets had a significant gain in popularity compared with 2007-2008. On the other hand, low-fat and low-cholesterol diets dropped off significantly in popularity, possibly due to the recent rising trend for the ketogenic diet, the researchers speculated.
Adherence to special diets also varied according to sex and race. Specifically, women tended to diet more than men, with 19% of U.S. women reported being on a diet on any given day vs 15.1% of men. And more than 20% of women over the age of 40 adhered to a special diet, the data showed.
More so than any other race, white adults were more likely to adhere to a special diet, with about 18% of non-Hispanic white adults reporting sticking to a diet. About 16.4% of Hispanic adults stuck to a diet, while only 14.7% and 14.9% of Black and Asian adults, respectively, reported dieting.
When broken down by educational levels, those holding college degrees or a higher degree were more likely to adhere to a special diet (18.6%). Special diets were less common among those with less than a high school education (14.1%) and high school graduates (17%).
Special diets were also far more popular according to weight status — with a significant linear trend with increasing weight. Specifically, more than 23% of all adults with obesity said they adhered to a special diet on any given day, the results showed.