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One Sunday around midday, Faith rang me up in the house in Clapham. She had bought this amazing book that explained why we put on weight and she must come round and share it with me.

It was a beautiful summer day, so we settled ourselves in the back garden with a jug of iced tea. On an afternoon like this the garden was a sun-trap. I laid myself out on a battered lounger; Faith sat in a wicker chair and put her bare feet next to mine. She was excited about her new find, so I lay back with the sun full on my face and waited for her to divulge all.

‘If you believe this book, dieting is just crazy,’ began Faith. ‘Not only does it not work—in that the weight always goes back on—but dieting actually encourages you to get fatter each time you do it. Listen to this.’

Faith read:

‘In our minds we know the difference between going on a diet and being subjected to famine or starvation. But our bodies do not know the difference. When we go on a diet regime we activate the mechanisms in the body that protect us in times of famine. And what does the body need to keep it going between times of famine? Fat. The more often someone diets, the more their body will protect their stores of fat. (page 50)

‘…Diet regimes have the effect of wasting lean body tissue. If the diet is severe or takes the form of a fast, much tissue lost will be lean body tissue. (page 51, Geoffrey Cannon and Hetty Einzig,  Dieting Makes You Fat, Century Publishing , London, 1983)

‘Basically that means repeated dieting eats away your muscles, because the best way to survive starvation is to lose muscle and build up fat. After a few draconian diets, you end up with a fat-loaded body designed to withstand famine,’ Faith summarised. ‘The other amazing thing is how the body adapts to having fewer calories available. Listen carefully to this:

‘Dr Marian Apfelbaum investigated what happened to the people of the Warsaw Ghetto during the two years of famine during the Second World War…(page56)

‘Yup this is it: this is the amazing bit. They were eating only seven or eight hundred calories a day, seventeen hundred calories a day less than they had before the war. So over two years they suffered a shortfall of over a million calories. Well, a million calories is equivalent to about 150 kilos of body fat, so the fat in their bodies—say about fifteen kilos in a normal person—would have only provided a tenth of the missing calories. Instead of getting thinner and thinner, their bodies economised by nine hundred thousand calories over two years!  In fact, with their shrunken muscles and what-not, they actually got down to a point where they were burning less than one thousand calories per day.’

Faith read several more examples all pointing to the same conclusion: dieting slows down your metabolic rate, so your body burns fewer calories each day. You eat, say, fifteen hundred calories a day on a diet, but your body reacts not by reducing its fat stores, as you want and as the Bath Tub theory assumes, but by burning fewer calories. 

That would explain why you hit a plateau when you diet. You stick to the calorie limit set, but your body adjusts its calorie burning down towards that limit. You end up starving yourself for nothing because your body lamely accepts that it must survive on the lower ration. 

I thought about a recent weekend when I’d been visiting a superstore for my usual fix of DIY kit. I’d had to sit down on a pile of upturned orange buckets until I felt strong enough to lift down the chipboard shelving I wanted. I was feeling dizzy, having had no breakfast and having stuck rigidly to one thousand calories a day for three weeks. On that Saturday morning I had kept myself going with the thought that I had just three pounds to go to get back down to nine stone. I winced. I hadn’t even achieved the nine stone on that occasion, and I was already back to about nine stone seven.

Anyway, Faith was pushing on with her next revelation: ‘To some extent, it works the other way too. If you eat too much, your body adapts by burning more.

‘Over-feeding does not make you thin, of course, but it does speed up the rate at which the body uses energy. After over-feeding, a person’s metabolic rate when asleep and at rest speeds up, as does the energy given off as a direct result of eating. Most remarkable of all is the effect on the energy used when exercising. In one study the oxygen consumed by people who were over-eating increased by 30 percent during walking, 25 percent during cycling and 19 percent during stair-climbing.’ (page 62)

I squinted up at her in the sunlight. ‘It makes perfect sense that your body should use more calories when they are plentiful and use less when it has less available. I mean, that is just the same as for sleep. Maybe every night our bodies would like an extra hour, but the alarm goes and we drag our butts out of bed. That means a deficit of 365 hours per year, but we don’t expect to have to catch those hours up, we expect the body to adjust to the amount of sleep we give it.’ 

Faith continued, ‘When you think about it, it would be odd if the only way we had of regulating our fat stores was by weighing ourselves and counting calories. What would animals do? Just spare a thought for the average rabbit. Nobody publishes a calorie chart for grass and daisies, and it’s impossible to hold a calculator with those little furry paws. Six extra buttercups a day through one lush summer and never mind how you look in a bikini, what about hopping away from a non-dieting fox! Cows do not get obese even though they stand knee deep in food all summer. The body has to have a way of keeping it all in balance.  The scientific name is homeostasis.’

Once you think about it, it is difficult to argue the contrary to homeostasis, that weight is simply the accidental, or conscious, matching of input and output. If bodies did not have a weight regulating mechanism, how could wild animals (say, birds, monkeys or rats), who know nothing of calories or bathroom scales, steer between obesity and emaciation? We find it completely obvious that if a man takes on a heavy manual task for a day he will be really hungry come supper time. Why should homeostasis apply to all other bodily functions (water, salt, oxygen, temperature, sleep) but not to calories and fat stores? Fat and energy are vital to all animals, so it is unimaginable that bodies would ignore this balance while monitoring all the others.

Energy homeostasis was an important new idea for me that would, over time, transform my life. Homeostasis would from now on become my key to solving overweight. Naturally slim people are not making an effort to stay slim. They are in a state of natural balance, with their hunger deciding when they should eat. But how could I recover that natural balance? Indeed, how had I lost it?

‘Well, go on then, Faith. So far, you have explained that whatever we do, starve or overeat, we should stay the same weight. I thought you were going to explain how we get fat. Tell me why energy homeostasis works for any stupid rabbit stuffing dandelions, but does not work for me. Tell me why my homeostasis has broken down. Go on, I’m really interested.’ 

So Faith went on to describe what she called ‘the diet ratchet.’

The first important idea is that your body cares how fat it is, it has its opinion. That is what we mean by homeostasis: the body will maintain and protect its desired level of fat. The next important question is: How will it decide the level of fat it wants? Well, that opinion is not based on some once-and-for-all decision (like temperature at thirty-seven degrees), it varies with the circumstances that the body experiences. So when the body—Id, you could say—experiences famine, he does the economising business that we’ve just seen, but when the diet is over, Id has changed his mind about how much of a fat store he wants.

Suppose, originally, your body has fifteen kg of fat. You go on a diet and lose six kg of fat and muscle (and indeed water and glycogen). During this period of starvation, your body concludes that it would be a good idea now to have a stock of seventeen kg of fat, in case a famine re-occurs. Common sense, just like we think of stocking loo rolls or petrol if there has once been a shortage. So when you finish the diet, your body makes you feel extremely hungry.

You binge because you feel famished, and you nibble because you feel peckish.  The body rebuilds a seventeen kg fat-store pretty quickly because even if you eat normally—say, two thousand calories a day—your lower metabolic rate and shrunken muscles consume fewer calories. You are soon two kilos heavier than when you STARTED the last diet, so you feel you MUST go on another diet, and the whole vicious cycle is ready to turn again.

Faith had dubbed the cycle the ‘diet ratchet’ because each time you diet you incite your body to choose a higher target weight. Yo-yo dieting is the wrong term because a yo-yo does not climb higher each time it rises.

Normal homeostatic people find it hard to put on weight. If they eat more than their bodies want, they feel uncomfortably overfed. They can only put on a limited amount of weight by forcing themselves to overeat. Dieters have found a trick to make their bodies want to put on weight. As dieters develop the fear that their weight will rise indefinitely, their Ids develop a corresponding terror that famine is now the permanent way of life. 

‘That is amazing,’ I gasped when she paused. ‘It is the most bitterly ironic thing that I’ve ever heard in my entire life! It makes so much sense to me. It’s like this: if you walk around in high heels you get calluses on your feet. You scrub them off with a pumice stone. That works; it leaves your feet soft and pink. But when you abrade the rough skin on your feet with a pumice stone, you can reasonably expect your body to re-build that skin even tougher, and a life of pumicing beckons. Dieting by calorie control is just as short term, and just as counterproductive, as sandpapering your feet. It works, it takes off the pounds, but it is not a permanent solution. This explains so much!’

Faith was laughing happily at my runaway enthusiasm. ‘It’s the law of reversed consequences. Pure Nietzsche. Instead of “What doesn’t kill you makes you stronger,” it is: “What doesn’t starve you makes you fatter!”’ 

At last I understood why I could diet successfully for a period only to find my weight creeping back on once I handed over control to my appetite. I understood how I could put weight back on even without eating more than the allowance recommended by the Bath Tub theorists. I understood why, at times, I could be so damn greedy.

Homeostatic people never get more than mildly hungry. They eat within a couple of hours of feeling peckish, and one normal-sized meal brings them back to satiety. When dieted down people are hungry, they are not satisfied simply with a full stomach. They have ‘suppressed hunger’ for all the fat their Ids feel has gone missing. Perhaps this is five kg of body fat, a shortfall of 5 x 7,700, that’s 38 000 calories. This would mean eating solidly for a couple of weeks and being hungry all that time.

Like Henry and me after the Scarsdale Diet.


The Diet Ratchet