Do Preferences In Diet Matter For Weight Loss

sharma-obesity-fat-dietingAs regular readers are well aware, obesity is a chronic disease which simply means that any treatment you decide to pursue needs to be one you can stick with in the long-term (this applies as much to your diet as it does to taking an anti-obesity drug or, for that matter having surgery – when the treatment stops the weight comes back!).

That said, it would be easy to assume that if you chose (or otherwise have a say) in the kind of diet you think will help you manage your weight, you’d a) lose more weight and b) be more likely to keep it off.

As a randomised controlled study by William Yancy Jr. and colleagues from Duke University Medical Center, Durham, North Carolina, published in the Annals of Internal Medicine, neither of these assumptions may be true.

The researchers randomised 207 participants to two groups – a choice group in which participants had the choice of going either on a low-carbohydrate (less than 20 g/day) or low-fat diet (less than 30% energy from fat).

The non-choice group was not given this choice but were randomly assigned to either of these diets. Both groups were provided with group and telephone counseling for 48 weeks.

Of the 105 choice participants, 58% chose low-carb and 44% chose low-fat – 83% completed the study – and lost on average 5.7Kg.

Of the 102 non-choice participants, 52 % were assigned to low-carb and 48% to low-fat – 86% completed the study – and lost on average 6.7 Kg.

Of note, the actual reported intake of carb in the low-carb groups ranged between 45-80 g of carbs per day (down from about 200 g/day) while fat intake in this group increased from about 40 to 55% of total energy); In the low-fat group, actual fat intake, fell from about 40% at baseline to about 35% on the diet.

There were no difference in dietary adherence, physical activity or quality of life.

This study illustrates that whether or not you get to chose your preferred diet or not doesn’t matter – what does is that you stick with it.

Or as the authors put it,

“The double-randomized preference design of our study allowed us to determine that preference did not meaningfully affect weight loss. Moreover, the range of estimated weight differences between groups in the 95% CIs does not contain a clinically meaningful difference in favor of the choice group.”

Both findings may not be exactly what one may have predicted – which is exactly why we need these types of studies.

Edmonton, AB