This is an online debate Helen Pluckrose and I had at the unfortunately defunct website letters.wiki in 2020 and 2021. I’m posting it here for preservation. I’m not sure I got all the formatting right, but I did my best with it.

I haven’t changed the words at all, even where I’d like to.  :-)

Thanks to Helen Pluckrose for her kind permission to reprint her letters here.

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Does Dieting Work?
By Barry Deutsch & Helen Pluckrose

5 Letters

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Letter 1
By Barry Deutsch
Created 26 May ’20

Dear Helen,

Hi! I’m writing to respond to your open letter, “on Fat Scholarship and Activism.”

A thousand words seems cruelly scant to me, but I’ll do my best.

For space reasons, I won’t dig into our “obesity vs fat” semantic disagreement. I suggest we each use our preferred word, neither making a fuss about the other’s choice. (Ditto for “fat acceptance” vs “fat activism.”)

Part 1: Your charges against the fat acceptance movement.

Your criticisms of fat acceptance are a mix of cherry-picked examples and uncharitable readings.

For instance, you say where fat activism “could oppose discrimination against obese people in the workplace, it goes on about ‘romantic discrimination.’” But the linked article contains only three paragraphs about “romantic discrimination,” a fraction of a much longer piece. (And do you really think cultural components of attraction aren’t worthy of being written about? I can’t agree.)

Your claim that fat acceptance “doesn’t do this kind of work” – meaning opposing things like workplace and medical discrimination – is staggeringly wrong. I could provide a hundred links of scholars and activists addressing those issues, but since time  is limited, hopefully just ten will prove my point.

Your other indictments followed a similar pattern, but with only 1000 words, I must move on!

(This article by Angie Manfredi, aimed at teens, is a non-comprehensive but accurate overview of fat acceptance’s goals. And Yasmin Harker created this useful bibliography of academic works about fat rights and fat discrimination.)

Part 2: Why I’m Generally Anti-Diet

We both want to end stigma and discrimination against fat people. Where we disagree (if I’ve understood correctly) is that you think fat people should try to not be fat, and that fat people are by definition unhealthy.

Accepting for a moment, for argument’s sake, that fat is unhealthy, that doesn’t necessarily lead to the conclusion that most fat people should try not to be fat.

First, I’ll stress that no one is under any obligation to maximize health. Exercise and cooking can take time, space, money, and mental energy which not everyone has. And people can legitimately prioritize other things.

But some fat people do wish to prioritize their health. Shouldn’t those fat people be encouraged to lose weight?

Some should – people with specific, serious conditions that weight loss could help (even if they’d still be fat).

But for 99% of fat people, I’d say not. The evidence is clear that weight-loss plans don’t work for the large majority. Most never lose a significant amount of weight – certainly not enough for a fat person to stop being fat. And usually whatever weight is lost – or more – comes back within five years. This causes mental anguish, because failure to lose weight, or to maintain weight loss, easily turns into self-hatred. If the person tries multiple times (as is common), the physical effects of yo-yo dieting can be very harmful.

Wayne Miller, an exercise science specialist at George Washington University, wrote:

There isn’t even one peer-reviewed controlled clinical study of any intentional weight-loss diet that proves that people can be successful at long-term significant weight loss. No commercial program, clinical program, or research model has been able to demonstrate significant long-term weight loss for more than a small fraction of the participants. Given the potential dangers of weight cycling and repeated failure, it is unscientific and unethical to support the continued use of dieting as an intervention for obesity.

Am I saying fat people who want to be healthier should give up? Absolutely not. I’m saying becoming healthier doesn’t require futile attempts to lose weight.

Please look at this graph. (Source.)

It shows likelihood of mortality as it relates to weight and four other characteristics: fruit and vegetable intake, tobacco use, exercise, and alcohol. These are sometimes called the “healthy habits.”

On the left side of the graph, fat people who practice no “healthy habits” – smoking, no veggies, immoderate drinking, no exercise – have a much higher mortality risk than so-called “normal” weight people with unhealthy habits (although the “normals” have elevated risk too).

On the right end of the graph, fat people who practice all four healthy habits have a mortality risk that’s just barely higher than their thinner counterparts. More importantly, we can see that fat people who practice all four healthy habits benefit enormously, compared to fat people who don’t. (“Normals” benefit enormously from these healthy habits, too.)

Most fat people can’t permanently lose enough weight to stop being fat. But most fat people can eat more veggies, can not smoke, can limit ourselves to one glass of hootch a day, can add moderate exercise to our lives. These things aren’t always easy, but they are all much more achievable, for most fat people, than stopping being fat.

Achievable advice is better than unachievable advice. There’s a positive way forward for most fat people who want to be healthier – one that’s more likely to work, and less likely to encourage self-hatred, than trying to stop being fat.

One final thought: stigma against being fat may be more harmful than fat itself.

These findings suggest the possibility that the stigma associated with being overweight is more harmful than actually being overweight… Growing evidence suggests that weight bias does not work; it leads to greater morbidity and, now, greater mortality.(See also.)

Could we get rid of weight bias while still holding the belief that fat people must lose weight? I doubt it. Reducing stigma could do more for fat people’s health than reducing waistlines.

There’s so much more to say (harms of dieting; benefits of a Health At Every Size approach; how HAES can help with disordered eating; etc), but I’m out of space.

I hope this letter finds you happy, well, and socially distanced someplace very cozy.

Best wishes, Barry

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Letter 2
By Helen Pluckrose
Created 26 May ’20

Dear Barry,

Thank you for responding to my open letter.

They are not cherry-picked examples unless you mean that I am picking examples of elements of fat activism that worry me and only criticising them. This is quite a standard practice.

I know that fat activism and fat scholarship can address important issues but this is why it is so frustrating when it focuses on “fatphobic” discourses instead. I learnt about the connection between poverty and obesity and about medical discrimination in the Fat Studies Reader and these are things that could be focused upon empirically. Unfortunately, it spends much more time going on about fatphobia and how science is bad.

I think claims to be ‘anti-diet’ are missing the point and it also encapsulates the misdirection that fat activists frequently engage in.

There are two definitions of the word ‘diet.’ One refers to what someone eats and the other refers to a short-term weight loss plan. I think we can safely assume that we are both in favour of people eating and both against short-term weight loss plans.  Short-term weight loss plans cannot achieve a long-term healthy weight by definition. In the same way a six-week non-smoking plan after which you go back to smoking cannot achieve long-term non-smoking. Nevertheless, the reason the majority of people (worldwide, not in America) are not obese is their diet. Either intuitively or consciously they eat the right amount of calories they need to be neither dangerously underweight or dangerously overweight. The scientist you cite as saying there is no evidence that weight loss plans can achieve long-term weight loss is necessarily right but he seems to be talking to the people who only tried short-term ones and he might get different answers if he asked people who are not overweight why they are not. Some, like my husband (curse him) will doubtless say they don’t have to think about their diet to maintain a healthy weight but others, like most of my friends, will say they do it by watching what they eat.

You urge me to consider that cultural components of  attraction could be worth writing about and I don’t necessarily disagree. I do, however, think we should pay more attention to cultural components of obesity because it kills people.  Even in the countries like mine and yours where obesity has reached epidemic proportions, this was not the case 100 years ago or even 50 years ago. The fact that mass obesity is such a new phenomenon in some countries but still not in others indicates that it is not a biological inevitability but a product of culture. The fact that it is a causal factor for so many diseases and early death means we should try to do something realistic to address this. I agree that simply telling people to eat less and move more is likely to be unhelpful.

I agree that no-one is under any obligation to maximise their health. I have little sympathy with libertarian views that use obesity as an argument against people being required to contribute towards a nationalised healthcare service. My own father was assertive in his decision to smoke and he maintained that he was right to choose a more enjoyable life over a longer one even when he was dying of lung cancer.  I absolutely support him in that although, selfishly, I’d rather he were still alive.

I agree with this:

Achievable advice is better than unachievable advice.

However, I am sceptical of this:

But most fat people can eat more veggies, can not smoke, can limit ourselves to one glass of hootch a day, can add moderate exercise to our lives. These things aren’t always easy, but they are all much more achievable, for most fat people, than stopping being fat.

It seems unlikely to me that people who find it very difficult to refrain from eating too many calories will find it much easier to commit to more vegetables, not smoking, drinking in moderation and exercising. However, I agree that thinking of weight loss in terms of making healthier choices is more likely to be helpful than thinking of it as stopping being fat.

I think you are being defeatist. What the evidence that people find it very difficult to  lose weight and maintain that weight loss suggests is not that obese people should stop trying to lose weight and maintain that weight loss but that the currently advocated ways for doing so are not adequate. We know how people get fat and stay fat. What we are failing to address is why they do so. This is what we need research into on both a social and psychological level. What has changed in society that makes obesity an epidemic right now? Why do so many people find maintaining a healthy weight so difficult psychologically? What will realistically help them overcome this?

Your thesis seems to be: Obesity is unavoidable so we can either continue to have a stigma against obesity and make fat people both fat and miserable or we can get rid of the stigma against obesity so that fat people can be fat and happy.

Mine is: Obesity is a new problem so we know it is avoidable. We can put our efforts into problematising the people addressing obesity as a problem or we can address the problem of obesity while also addressing  discrimination & stigma and not being arseholes to obese people.

Best

Helen

P.S – Yes, I am self-isolating quite comfortably, thank you. My husband has had to take a furlough from work to protect me because I am particularly vulnerable to complications of the coronavirus because I am obese. :-p

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Letter 3
By Barry Deutsch
Created 07 Jun ’20

Dear Helen,

Thanks for responding!

Our disagreements are legion but our word count isn’t, so I’ll get right into it.

You’re right, it’s not cherry-picking to criticize specific claims. But it is cherry-picking to treat an unrepresentative example as representative. You cherry-picked several times, such as saying fat acceptance doesn’t address workplace and medical discrimination but instead “goes on about romantic discrimination.”

You deny Dr. Miller’s claim that no “weight loss diet” has been shown to work[*] in a peer-reviewed study, by saying  “diet” means only “short-term” weight loss plans, a distinction not found in any dictionary I checked. As Dr. Miller’s quote said, he was looking at “long-term” weight loss.

No commercial program, clinical program, or research model has been able to demonstrate significant long-term weight loss for more than a small fraction of the participants.

Not a single weight-loss model – including long term approaches – has ever been shown to work in a peer-reviewed controlled clinical study.

There have been hundreds of tries. Anyone with a method scientifically proven to really, permanently work would become a billionaire. And yet, as Mann points out, not a single weight loss plan can even meet Medicare’s standards for effective health treatments.

Reviews of the scientific literature on dieting generally draw two conclusions about diets. First, diets do lead to short-term weight loss. One summary of diet studies from the 1970s to the mid-1990s found that these weight loss programs consistently resulted in participants losing an average of 5%–10% of their weight. Second, these losses are not maintained. As noted in one review, “It is only the rate of weight regain, not the fact of weight regain, that appears open to debate.”

(When Mann says “diet,” she doesn’t mean only short-term plans.)

Weight-loss advocates deny this reality – a finding that’s been in scholarly papers for decades and is unchanged today. They insist that empirical results don’t apply to whatever approach they favor (often called a “lifestyle change”).

Whatever they call it, it’s never been proven to work.

If we can’t acknowledge that, how can we have a real conversation about what fat people should do?

It is irresponsible for society to pressure us to stop being fat, when there’s no effective method for permanently losing even 5-10% of body weight, let alone the much larger amount someone like me would have to lose to stop being fat.

Now consider that weight-loss plans often leave people at higher mortality risk, less happy, and – by the way – fatter than when they began.

Proposing a treatment for being fat that’s more likely to harm patients than work isn’t just irresponsible. It’s cruel. Especially when there’s a better way.

Helen, you were skeptical that fat people could successfully pursue other routes to health, like exercise, not smoking, drinking moderately, and eating their veggies. Even though you were responding to an empirical study that included many fat people who did exactly those things.

(Are fat people especially bad at quitting smoking? This study found no connection between weight and ability to quit smoking; another found fat smokers were better at quitting.)

The truth is, keeping weight off is much harder than eating veggies or moderate exercise. Probably even harder than quitting smoking. Because our brains don’t want us to lose weight. Neuroscientist Sandra Aamodt explains:

The root of the problem is not willpower but neuroscience. Metabolic suppression is one of several powerful tools that the brain uses to keep the body within a certain weight range, called the set point. The range, which varies from person to person, is determined by genes and life experience. When dieters’ weight drops below it, they not only burn fewer calories but also produce more hunger-inducing hormones and find eating more rewarding….If someone starts at 120 pounds and drops to 80, her brain rightfully declares a starvation state of emergency, using every method available to get that weight back up to normal. The same thing happens to someone who starts at 300 pounds and diets down to 200.Even years after losing weight, our brains may still be trying to get us to regain the weight, preserving calories and making us hungrier. That’s why so many dieters gain weight in the end.

Because no comparable brain process keeps us from adding walks and veggies to our lives, most will find those things much easier than permanently losing substantial amounts of weight.

(I want to emphasize to readers, again, that no one’s obligated to maximize their health. And not everyone has the opportunity, unfortunately. A rare thing Helen and I agree on!)

It’s irrelevant to discuss if fat people should lose weight, when there’s no reliable way to make that happen.

You called me a defeatist, but I’m not. Knowing that fat people can be happy and healthy and lead great lives is the polar opposite of defeatism.

Imagine two people in a smelly mud pit behind a wall. On the other side of the wall, a beautiful park. The first says “with enough effort, I can vault this wall like Jackie Chan and be happy on the other side.”And so she tries and tries, always failing, while denying there’s any other way to reach the park.

The second realizes she’s unlikely to ever vault like Jackie Chan. So she walks around the wall instead, and is happy in the park on the other side.

Is the second person the defeatist?

I’m out of space – and there’s so much left unaddressed! Let me know if I skipped anything you especially wanted addressed, and I’ll try to fit it in my next letter.

Hoping this finds you safe and happy,

Barry

[*] I’m using “works” as shorthand for “significant, sustained weight loss for most people.”

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Letter 4
By Helen Pluckrose
Created 07 Jun ’20

Dear Barry,

OK, fair enough. I could have phrased that better so it was clear I didn’t mean that they weren’t doing that but that they weren’t sticking to that.

Not a single weight-loss model – including long term approaches – has ever been shown to work in a peer-reviewed controlled clinical study.

I think it means that people who went on short-term diets did not succeed in keeping the weight off afterwards. It simply isn’t possible that people ate fewer calories than they burned and got fat or that got slim and then ate the same number of calories that they burned and got fat. Fat needs to be built or maintained with calories. If it were really true, we’d see evidence of it in areas where food is scarce. There’d be a number of thin people and some who were obese saying “I don’t understand it. I barely eat a thing.”

Anyone with a method scientifically proven to really, permanently work would become a billionaire.

What’s the method that explains why most people aren’t fat? Why aren’t I fat when I eat 2000 calories a day but get fat when I start eating more than that? Surely, the thing that isn’t working is people finding a way they can stick to? That’s not a judgemental thing. I’m not actually a believer in free will. I don’t think people who find they can’t stick to the number of calories they need are lazy or undisciplined. I think it’s really hard for them and medical research should look into making it easier.

Weight-loss advocates deny this reality – a finding that’s been in scholarly papers for decades and is unchanged today.

The first study here talks a lot about how severe the psychological effects of feeling deprived can be and refers to this as being undernourished. However, it clearly says that if people stick to this, it works. “A small minority of patients, able to endure the hunger and emotional hardship of treatment and to sustain their undernutrition for years of maintenance, feel that the sacrifices have been worth the effort.”

The second one clearly says that people gain weight again due to a number of factors and then it says,”Those individuals who do sustain substantial weight loss over time generally must maintain high levels of dietary restraint, physical activity, and self-monitoring behaviors.”  Of course.

The third one looks at obesity as a psychological issue but clearly says that the problem is that weight loss programmes are short-term .  “Weight loss ads and commercials bombard the media, including social media, with diets and other products claiming to result in large amounts of weight loss. There is little focus on long-term maintenance.” Later, it refers to the regaining of weight as ‘recidivism’ which clearly indicates that people have ceased sticking to a diet that will enable them to keep the weight off.

In summary, all three of these papers  acknowledge that when patients do stick to a diet programme long-term, they stay slim long-term. However, nearly all of them find this too difficult and revert to overeating.  They all recommend other measures to minimise the impact of obesity on health than sustaining weight loss which indicates that obesity is a problem for health. There is much to be said for these arguments especially if faced with the realistic option between working with what we’ve got – obesity with health risks minimised – or nagging people to stay on a diet forever when they do not feel they can. The papers also provide some useful information about how yo-yo dieting can affect metabolism and the physiological effects of weightloss which can often function to make weight loss harder so there are some physiological causes of weight plateaus and losing weight becoming harder after some has been lost.

You acknowledge some of the physiological symptoms when you say,

Even years after losing weight, our brains may still be trying to get us to regain the weight, preserving calories and making us hungrier. That’s why so many dieters gain weight in the end.

And you make a plausible argument that doing various things for living a healthier lifestyle could be easier for many people than eating less. It isn’t for me. I have managed to lose weight and keep it off all the times I have not been taking centrally-acting medication but have never been able to give up nicotine, wine or chocolate. Of course, this may indicate that I do not have the same problems that many obese people have.

I think the difference of opinion we are having here is between my view that weight loss and maintenance is physically possible but psychologically hard and so the solution must be psychological. I want more effort going into looking at it psychologically. And environmentally.  I still think research into why there was so much less obesity in our grandparents’ generation and trying to recreate that would be worthwhile. I am not ready to settle for being obese. I have been slim for most of my life and it is so much more comfortable and makes doing almost anything so much easier.

You, on the other hand, think there is a need for acceptance and mitigation of health risks, not because you are being defeatist, but because you’d rather spend your life that way than to keep trying and, statistically, being very likely to keep failing to lose weight. I think that is a perfectly reasonable analysis of the situation and decision to come to. When I say I want more focus on the individual’s psychology in order to find personalised solutions and not rely on formulaic programmes which work physically but not psychologically, I think some people’s psychology might reveal that they want to do what you want to do.

Best

Helen

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Letter 5
By Barry Deutsch
Created 02 Feb ’21

Dear Helen,

Of course if someone eats little enough, they will lose weight. And if they keep eating little enough forever – which may require eating even less than when the diet began, as their body attempts to regain the weight – they can keep the weight off.

In this extremely superficial sense, it’s true that all fat people can diet their way to no longer being fat.

But that’s sidestepping the real question: Can a typical human voluntarily reduce food intake enough to cause a large loss of weight, not just for a few months or years, but for a lifetime? Not just in theory, but in practice? Study after study has shown that the overwhelming majority of us cannot.

You don’t deny that this is the case (thank you!), and say medicine should work on changing this. But it’s been working on it, for longer than we’ve been alive, without success. And in the meantime, trying and failing to lose weight (including in the form of multiple weight losses and regains) is harming many people’s mental and physical health.

Unless something in the science changes, the large majority of fat people will never be able to deliberately lose enough weight to stop being fat – and most weight lost, will eventually be regained.

That’s one thing “fat acceptance” means – just accepting that fact.

If there’s one thing I’d like people to take away from what I’ve written here, it’s this: It’s useless to say “fat people should stop being fat” when there’s no pragmatic, safe, and sustainable way to make that actually happen for most fat people.

Since this is my final letter in our exchange, I thought I’d finish up by listing some changes this fat activist wants to happen.

1) I want every fat person to choose for themselves if they want to try dieting their way out of being fat – but without being pressured.

2) But I also want fat people to have full and truthful information before deciding. They should know that – for those fat people who want to work on their health (and not everyone does, or should be expected to) – simple techniques like eating more vegetables and moderate exercise have been proven enormously beneficial, and this is true even if they remain fat.

They should know that the overwhelming majority of fat dieters don’t lose enough weight to stop being fat, and often end up fatter than when they began. They should know that multiple cycles of weight loss and regain are harmful physically and, for many, mentally – and are a far more likely outcome than permanent weight loss. They should know that it’s the body’s natural defenses against weight loss – not being weak-willed or contemptible – that make it effectively impossible for most people to keep large amounts of weight off.

3) Direct anti-fat discrimination and exclusion – from employers and doctors and teachers and engineers and clothing designers and so many others – has to stop.

4) Anti-fat stigma should stop as well, as much as possible. If we’re genuinely concerned about fat people’s health, then this should be a no-brainer; the damage to health from being stigmatized is fairly well documented.

What would ending anti-fat stigma look like? A full answer to that question would require thousands more words. But we could begin by changing the way our major institutions (such as schools, children’s books, television and movies) depict fat people. Ordinary fat people leading ordinary lives would ideally be as common on TV shows as we are in life, while anti-fat stereotypes become much rarer. (To be clear, I’m talking about creating these changes through persuasion and consumer advocacy, not any form of censorship).

5) Probably the hardest part: As a society, we have to stop teaching fat people to loathe ourselves.

Which I think begins with fat acceptance. In fact, all these changes are part of fat acceptance.

Thank you for this exchange. And in particular, thank you for how you’ve engaged this topic with me. It’s been difficult to find anyone who will disagree with me about fat acceptance politely and thoughtfully; abuse and contempt are more common. (Which is, I suspect, one reason most pro-fat people hesitate to get in these discussions.)

In our exchange, you’ve mentioned your own plans to stop being fat. I genuinely wish you nothing but success with that. But whether or not you succeed, I wish you happiness.

Best wishes, Barry