11 March 2019

ROI on Weight Loss Interventions

Return on investment for weight loss interventions.

this graph shows the estimated return on

investment per dollar for various health problems this data was produced by the Copenhagen consensus and is targeted towards the United Nations so this is from a global perspective many of the investments would have little to no effect in developed nations but salt and tobacco are two very relevant interventions for every dollar invested into discouraging excess salt consumption it is estimated that 39 dollars of value is generated with tobacco you get a 22 dollar return weight loss interventions are not on this list how do they stack up compared to these other issues first of all we have to ask ourselves do weight loss interventions work at all often they do work initially but in the long run the weight is gained back often participants end up heavier I don't know of any randomized control weight loss studies that have long-term follow-ups I do however know of a study that looked at thousands of overweight metabolically helping individuals and followed up after 18 years when they used the people who stayed the same weight as a reference they found that the people who lost weight were more than twice as

likely to die young so even if long-term weight loss is possible it may in fact be bad for your house but there are many studies that show a correlation between increased weight and higher mortality or medical costs and there are also other studies that contradict these studies so the next question is can we reasonably assume that correlation is indicative of causation a typical cost-benefit analysis for weight loss interventions will straight up assume that correlation and causality are essentially the same thing sometimes they are essentially the same thing when researchers noticed that HPV correlated with cervical cancer they made an HPV vaccine and then cervical cancer rate went down scientifically proving a causal link for a rare cancer which sometimes occurs in women who don't have HPV would be statistically almost impossible and would take decades scientists simply assumed HPV was causing cervical cancer and given that cervical cancer rates dropped after the vaccines were introduced it seems they were right it would have been unreasonable to expect scientific proof of causation before introducing the HPV

vaccine so it is always easy to cast doubt by demanding a higher standard of evidence and this is not always productive but in the case of weight and health there are many reasons to believe that weight does not determine how the only study I'm aware of that controls for socio-economic status found that very giving people were less likely to die than normal weight people the epidemiological evidence is all over the place it is obvious that there are many confounding variables but for the sake of this video I'm going to let this pass and simply assume that correlation is indicative of causation and that lowering people's weight will decrease mortality and medical costs the first study I found published in the International Journal of obesity gives a good idea of the cost this study has a long list of conflicts of interest they are funded by drug companies and one member works for Weight Watchers when the study is evaluating the effectiveness of Weight Watchers so their incentive is to report that weight loss is beneficial and cost-effective despite this they estimated the cost of weight loss through Weight Watchers as a

hundred and fifty one to two hundred and thirty one American dollars per kg so what is the cost to society of a person being obese again I just looked to the first article I found to ask this question this study doesn't declare any conflicts of interest but the general bias seems to be towards exaggerating the cost while simultaneously narrating the benefits of weight loss but even if I take the claim that an average obese person costs 554 Australian dollars or 399 American dollars per year at face value it doesn't seem worth it 399 US dollars is only going to buy about 2 kgs of weight loss which isn't going to do anything but is the average cost of an obese person really useful at all anecdotally I heard of a woman who was admitted to hospital and the nurses had to rub lotion on the ulcerated sores between her fat rolls one of the nurses did the math to try and figure out how much it was costing to treat this woman and estimated it at something like $20,000 a day this is just an anecdote but it draws to attention the fact that nobody seems to have published an estimation of the distribution of the

increased medical expenses some hospitals are installing MRI machines that are intended for cattle because they have patients that cannot fit into a regular MRI this obviously costs a lot of money but has nothing to do with your typical obese person who would easily fit into an MRI I heard of another lady who got turned down for government sponsored weight-loss surgery because she wasn't fast enough so she went and got as fast as she could so she wouldn't get accepted which she eventually did and then became thin weight loss surgery is expensive but not typical let's say that the average citizen costs a thousand dollars a year due to criminal activity does that mean I have created a thousand dollars of value if I stop someone from jaywalking obviously not because there is a big difference between the average cost of a citizen and the typical cost of a citizen the typical cost might be zero dollars and yet the average is a thousand dollars if one percent of the population is costing a hundred thousand dollars a year in the rest of the population could be costing zero dollars and you still get an average of $1,000 the same is likely to

be true of obesity a typical overweight or obese person in a typical year is likely to cost zero dollars in additional medical costs we have a continuum between two approaches here one would be a community-based approach focusing on a large and diffused problem or an us-and-them approach that discriminates against a small minority we have all been taught that discrimination is a bad thing there is a tendency to prefer defining problems as though they are communal even in cases where this is ridiculous for example I heard a publicly-funded radio program in which they interviewed a criminal who blamed all of society for her many crimes the message of the program was about shifting the blame from the few repeat offenders to the entirety of society which I completely reject the problem is that you have a more introspective reasonable and responsive audience when talking to normal people so they are easier to deal with but the resulting worldview is simply inaccurate so the Weight Watchers study estimated it cost one hundred and fifty one to two hundred and thirty one American dollars per kg of weight loss

among typical obese people but the cost of these typical obese people is likely to be a lot less than average there were no extraordinarily fat people who participated in this voluntary experiment but for the sake of this video I will just assume that typical and average are the same I will run the math on a hypothetical case study to see how things add up in the long run let's imagine we have a woman who is 5 foot 8 inches and has a BMI of 30 - which means she needs to lose about 19 kgs in order to have a BMI of exactly 25 which would put her at the upper limit of what is considered normal weight 19 times the cost per kg equals two thousand eight hundred and eighty three to four thousand four hundred and ten US dollars assuming our participant does not drop out which many did it takes around six years for her to lose enough weight to be at the high end of normal weight but this is assuming a linear weight loss after the first year which in effect the weight loss is likely to level off so let's say it takes eight years for this weight loss to occur this puts the cost up to three thousand eight hundred forty four to five thousand

eight hundred eighty u.s. dollars over eight years this might be worth it if the patient were permanently cured for life but all longitudinal studies would seem to suggest this is not the case let's say that weight maintenance costs half as much as weight loss a Weight Watchers membership plus travel costs on average costs eight hundred and ninety six US dollars per year half of that is four hundred and forty eight US dollars we're a staying fat was only costing three hundred and ninety nine US dollars per person let's say our participant lives another forty years from the start of the intervention forty years - eight spent in the intervention is 30 - 32 times maintenance cost is fourteen thousand three hundred and thirty six dollars if we add that to the cost of eight years you get about eighteen to twenty thousand US dollars the cost of remaining obese on the other hand would be fifteen thousand nine hundred and sixty so there is a net loss of two to four thousand dollars for one person and this was using the private key model which was found to be more efficient than standard care provided by the government so we have a return on

investment of zero point eight four but this doesn't take into account the opportunity cost if we go back to the interventions I showed earlier focusing on salt has a return of $39 ensuring people who have had a heart attack take half an aspirin a day has an even higher return of $63 is to focus on obesity taking away from these other interventions I believe it is there is a large focus on sugar because it has calories that is taking away from a focus on salt so to recap on my methodology I first assumed that weight loss programs are effective long term which is highly questionable I then assumed long-term weight loss has desirable health benefits to supply evidence that the opposite is true I then assumed that correlation is causally linked again highly questionable I then assumed that a typical obese person cost similar to an average obese person which is very unlikely to be true we further assumed that no participants drop out despite all of these assumptions exaggerating the likely effectiveness of weight-loss interventions we still only come to an

ROI of 0.84 when we consider the opportunity cost focusing on obesity due to health concerns seems entirely ridiculous so even if you believe I am biased and somehow downplaying the seriousness of obesity I would have to underestimate the return on investment of weight loss interventions by forty six point four times in order for the ROI to be the same as focusing on salt and 75 times to compare to aspirin therapy this is an entirely first-world problem