Bringing harmony to public health debates about food

Christmas is coming, and it’s not just the geese that are getting fat. Celebrations over the holidays often revolve around gathering and feasting. In the northern hemisphere, baby it’s cold outside and the long, silent nights may contribute to seasonal variations in physical activity.12 Together, increased opportunities for eating and decreased propensity for physical activity likely contribute to the 0.4-0.9 kg weight gain found in adults home for the holidays.3

Mason and colleagues (doi:10.1136/bmj.k4867) target prevention of weight gain over the bleak midwinter holidays.4 Their intervention combined regular self weighing with written information describing seasonally adapted “10 Top Tips” to help habit formation,5 and a list of the physical activity caloric equivalents of common holiday foods they checked twice. Their randomised trial found an adjusted mean difference of −0.5 kg in weight gain at 4-8 weeks in the intervention group compared with controls.

It is intuitively attractive to focus on preventing weight gain during, rather than achieving weight loss after, the holidays. But focusing on individual weight change perhaps deals with the symptom, rather than the cause. Environmental factors are increasingly recognised to be potent determinants …