Partha Kar: Our approach to tackling obesity needs rethinking

Obesity is a focus of political and media discussion, since multiple datasets have shown that being overweight puts people at greater risk of serious illness from covid-19. But, if we want to improve the way we manage obesity, we need better research on what works in weight management—and a rethink of our approach to service provision.

NICE’s most recent guidance on identifying, assessing, and managing obesity was published in 20141: in the six years since, has there been no new evidence that would warrant an update? At that time, a lot of NICE’s recommendations were based on thin evidence, and NICE clearly accepted in its guidance that there were gaps in the research that needed covering. So, why hasn’t the research community or the National Institute for Health Research done the relevant investigations? The available evidence on diets from randomised controlled trials is equivocal at best and confusing at worst, owing to inherent bias, non-randomisation, and small participant numbers—especially when you try to look at long term impact.

I firmly believe that the evidence base for the “tiers” used in obesity management, and in the NICE guidance, needs reviewing. For the uninitiated, there are four tiers: the first two (which cover health promotion services, primary care, and lifestyle interventions) fall under the ambit of government, local authority, and public health; the next two (specialist weight management services and bariatric surgery) are the responsibility of local clinical commissioning groups.

Tier 3 (specialist weight management services) deserves particular attention for review, especially around its evidence base. One meta-analysis suggests that specialist weight management services provide benefit, although with caveats around data from single centre studies and variability in centre staffing.2

There’s also a question as to whether participants would have benefited from bariatric surgery earlier or whether innovations in medicine may have now opened up new treatment options, and whether such a review needs to be done by a specialist physician or by any trained prescriber.

If we want to be serious about obesity management, we need more focus on the societal changes needed to tackle it, rather than a simplistic narrative of lifestyle change and motivation, with the subtle (or sometimes overt) stigma attached to terminology and the implication of “not trying hard enough.” We should collect data on a national basis, do the necessary research, overhaul the archaic tier system, and try to have an open mind about all diets. The roles of NICE and Public Health England should be to evaluate all available data around dietary interventions, whether they be low calorie or low carb, and assess the impact not only on weight loss but on sustainability and long term impact—as the data suggest that this is a major issue with dietary interventions.3