Is Set-Point Theory the Reason Crash Diets Are Set to Fail?

Could restricting calories and going hungry actually make your body work harder to hold onto extra weight? Experts and science seem to think so...

Like same-day delivery and binge watching entire Netflix series on the day they drop, we generally don’t want to wait to get what we want. And the same is especially true when it comes to weight loss. 

But those quick-fix diet ads you see cluttering your social feed aren’t going to deliver the same satisfaction as a brown box landing on your doorstep within hours - and the results aren’t likely to outlast your Prime subscription either. 

“Crash diets are often nutrient poor and very low calorie which results in an initial loss of water weight, followed by further decrease in fat mass, but potentially also a reduction in muscle mass too,” explains consultant dietician and author, Ro Huntriss.

“The initial significant weight loss followed by slower ongoing weight loss can lead to frustration and psychological distress and the body will fight to return to its ‘set point’.”

What is set-point theory? 

Set-point theory is the idea that we have a pre-set, individual weight range wired within our genetics, and more specifically our DNA, that our bodies protect.

“The idea is that we all have an optimum range of weight that our bodies will work to remain within,” says registered nutritionist and junior CX nutrition manager at Huel, Jessica Stansfield, “and if we drop below this then our hormone system and metabolism will adjust to control it.”

It does this by ramping up ghrelin (the hunger hormone) and dulling leptin (the hormone that makes you feel full) to calibrate and slow your appetite accordingly and trigger hunger inappropriately. 

“The body also tries to preserve its stored energy, reducing rates of metabolism, meaning that weight loss can slow down to lower than expected considering you’re eating fewer calories than you’re using,” explains Huntriss.

Weight cycling

Cue weight cycling: a situation where you are constantly working to lose weight fast followed by gaining it back (and then falling back into losing weight again). Not surprisingly, this can be physically and psychologically harmful.

It’s suspected by some experts that weight cycling makes weight loss or gain harder in the future - but this hasn’t been scientifically proven.

“Overall, the theory suggests that your weight may fluctuate with yo-yo dieting but will ultimately return to the pre-set range,” says Stansfield.

Not all experts are convinced. “As with all theories, there are arguments against this as there are many factors that can and do influence weight such as diet, exercise, lifestyle and environment,” argues Huntriss. 

“Many people are able to successfully lose weight and maintain it in the long term, so the theory has not been fully proven.”

Can you change your set point? 

There is some good news if you’re currently struggling to lose weight and keep it off though. “While it’s a theory with evidence, there are unanswered gaps. But if we listen to the theory, then ultimately, yes, shifting your set point is doable providing you lose the weight gradually, without restriction and dieting,” explains Stansfield. 

Set point theory suggests that losing 10% of your body weight in stages and maintaining each step can help prepare the body to keep off the pounds.

The sweet spot: “Aim for a weight loss of one-two pounds a week to be sustainable in the long term,” advises Stansfield.

Your set point as you get older

But hang on a second. If we have a set point, why does weight tend to creep up in middle age at the mere whiff of a doughnut?

The bad news is that the system that keeps weight consistent in your younger years is believed by some researchers to misfire over time.

Resistance to hunger hormones leptin and insulin can develop and lead to weight gain. According to the theory, this and external elements gradually adjust the set point upwards as we age, which might explain why it's harder to maintain your weight in later life.

How to achieve sustainable weight loss

So, sustainable weight loss... how do you do it? We asked our experts to sum up the main points to keep in mind when it comes to losing weight, and keeping it off.

Take it slow

“As set-point theory suggests: weight loss is not a sprint, but a marathon,” stresses Stansfield.

“A meta-analysis of 29 studies in the US, looked into long-term weight loss maintenance and found that more than half of the lost weight was regained within two years and more than 80% within five.

“It also suggested that very low energy diets are no better in the long term.  The best thing to do is to move away from the term 'diet' and focus on positive lifestyle changes for good.”

The 10% that set-point theory advocates want you to lose at a time? That's the amount of weight you can lose before your body starts to fight back.

Maintaining your new, lower weight for six months is key to developing skills such as regular exercise, healthy eating, and stress reduction. Then you can repeat the cycle and reset your set point again by losing another 10%. 

Tailor your weight-loss journey to you

One person’s perfect diet is another’s downfall, so try a few things and find what works for you.

“When it comes to successful weight loss, there is not one ‘best diet’,” advises Huntriss. 

“There are lots of different ways in which a calorie deficit can be achieved and maintained including general healthy eating, low-carbohydrate diets, the Mediterranean diet, meal replacement drinks and intermittent fasting to name a few.

“For some people, they may actually just focus on habits and behaviours instead of focusing so much on the specific dietary changes and others may focus on psychology and mindset.

“The key to long-term success is finding something that works for you - not just thinking about what you can do for 12 weeks, but what you can do for life. It requires commitment and change and you have to be willing to sign up to that if you want to see long-term results.”

Eat intuitively

Don’t forget: “Listen to your body, and eat when you feel hungry,” says Stansfield.

In one study researchers found that, after four months, obese women who underwent an intuitive eating program lost more weight, had less abdominal fat, and were less stressed than those who did not.

Think about other lifestyle factors

“Don't put all the focus on diet. Get enough sleep, water, and exercise regularly too,” says Stansfield.

“Never underestimate the importance of sleep,” says Huntriss. “Adequate shut eye can help to regulate the hormones responsible for appetite and metabolism and can put us in an optimal mindset for positive health-related behaviours.”

Get enough of the good stuff

“Shift your mindset away from being restrictive,” says Stansfield. “Slow and steady, manageable changes are key.”

So what does that look like? “Consume a balanced diet with a mix from all of the food groups, and consume more vegetables. Perhaps aim for seven a day rather than five. Practice portion control, consuming a high level of protein and high fibre foods to help you feel sustained for longer periods of time.”

Want to cover all bases? Huel contains all 26 essential vitamins and minerals, carbohydrates, protein, fat, fibre and phytonutrients, and is naturally gluten-free. It’s a no-brainer.