This article is countering the term "diets don't work".

Debunking the “diets don’t work” myth

A catchphrase that’s gained a lot of popularity. Diets don’t work is a term spouted by experts a lot. It’s usually said for different reasons. Unfortunately, this term is factually incorrect.

Diets do work. In fact I’d go as far to say nearly all diets work.

However, It’s believed 95% of people who lose weight will regain it all back. That’s actually wrong, the figure is 80%. (1) However, that still is the majority and does show weight maintenance has a low success rate.

If your diet is able to get you to consume fewer calories than you burn, you will lose weight. (2)

So why is the term used so much?

They are quite a lot of reasons as to why. I mean this term does have some truth to it. Thew reasons this term is used a lot is because:

  • Most popular fad diets are awful
  • Most people who have dieted always end up back to where they started
  • Some people are predisposed to carry more weight
  • Lack of understanding about how diets work and energy balance
  • Hunger levels
  • Lack of activity
  • All or nothing attitude
  • Hunger hormones

The problem I have with a slogan like this, however, is that it’s very disempowering and unhelpful. If you’ve struggled to lose weight for the reasons listed above and someone tells you to just give up, because “diets don’t work”, that could be doing more harm than good.

I’m writing this to tell you, diets do work. You can lose weight and you can keep most of it off.

The problem is, it’s not that diets don’t work. But people are not taught how to keep the weight off and live properly afterwards or diet in a way, that they can actually enjoy the process.

Fad diets

When most people go on a diet, they tend to go on what I call a fad diet. It’s whatever is in fashion right now. Most fads come in peaks and waves. Just because it’s a fad doesn’t make it bad, it just means it’s used because it’s what’s popular right now.

Some example of fads, that have been popular are:

  • Intermittent fasting
  • Keto
  • Paleo
  • Atkins
  • 5:2
  • Juicing

The thing with all these fads are; they work by making you consume fewer calories. They either cut out a good group, eliminate meal windows or cut out tasty food which you just want to eat lots of. This is a good thing when it works. But the problem is people think these diets have a special magic. This leaves them with a rigid all or nothing mindset. (3)

If someone eats fruit on Keto they may feel like the diet is ruined, then either quit or binge.

This is the problem with fad diets is, people tend to struggle to stick with them. Then either relapse or quit soon. Cutting out food groups such as carbohydrates or cutting out sugar completely is difficult. The thing is, people just can’t stick to such extreme measures.

This is one of many reasons people say “diets don’t work”. As humans, we tend to get lured in by extreme measures, such as fad diets.

Old habits

It’s not that the diet doesn’t work, but it’s that people revert to old habits.

Let’s for example say, you did one of the fad diets above to lose all the weight. But you thought it was because of some special magic that caused the weight loss. This can lead to a problem, you now don’t know to maintain your weight going forward.

All those diets work by reducing your calorie intake. The problem is people go back to how they were eating before.

We’ll use a hypothetical example. Let’s say you’re a man that started at 250 pounds. Let’s say to maintain that 250 pounds, that means on average you were eating 4000 calories per day.

This chart shows why diets don't work. Most people go back to old habits.

Then you go Keto for example, due to not eating carbs and cutting out junk food, you were then eating on average 1500 calories per day. You then lost 70 pounds. You end up weighing 180 pounds.

Because you now weigh less, youre body requires on average 2500 calories to maintain, instead of 4000.

Here lies the problem, because you weren’t aware of calories, you don’t know this. So you slowly go back to your 4000 calories per day habit, before you know it youre back at 250 lbs.

It wasn’t the diet that failed. The diet worked. What didn’t work was that you had no maintenance strategy.

Yes this is very oversimplified, but this does happen.

To overcome this, I recommend using a calorie calculator regularly, to see what your maintenance estimate is. From there, you have something to work off and monitor.

Muscle loss

Another reason it seems diets don’t work is because of muscle loss.

Most fad diets don’t put any emphasis on protein content and resistance training. This is an issue. Without a basic resistance training plan and enough protein, your body will eat into its muscle stores as well as its fat stores.

When you’re in a deficit, your body is eating itself. If you’re not using your muscles and feeding them with protein, how is your body going to know it still needs them? When you’re on a diet, you’re starving your body of calories, so it breaks itself down for calories. It doesn’t care if it’s fat or muscle, it will just use what it can. But by eating enough protein and lifting weights, you’re stopping your body from eating its muscle. Therefore it only uses up fat mass.

Why is muscle loss an issue? Muscle is more metabolically active than fat. (4)

In simple terms 1kg of muscle will burn more calories than 1kg of fat.

Therefore if you went from 250 pounds to 180 but lost a lot of muscle, you’d burn fewer calories than someone who went from 250 pounds to 180 pounds, but kept most/all their muscle and lost mostly fat.

For example, both people could be at 180 pounds. But the person who ate plenty of protein and lifted weights may burn 2700 calories a day on average. Whereas the person who followed a fad diet, ate little protein and did no resistance training may burn 2500 calories on average.

All or nothing attitude

It doesn’t matter how you diet, to lose weight, you can eat whatever you want, whenever you want. You may want to read that bit again.

So long as you create a caloric deficit, over a period of time. That could be a week or a month, but if your net calorie intake is lower than your net output you will lose weight.

So what does that have to do with an all or nothing attitude?

The fad diets listed above, all have certain rules.

For example, on keto, you’re not to eat more than 20g of carbohydrate. So what happens when someone on Keto, who’s now feeling deprived of carbohydrates, caves in and eats a couple of slices of bread? They tend to feel guilty, they think they’ve ruined their diet.

They then feel like a failure, give up and eat all the carbs they feel deprived of in one sitting. But if they understood energy balance and calories, they would have realised they can still lose weight and eat bread.

The same could be said for fasting. What happens to someone who really hungry one morning, then caves in and eats breakfast. They think they’ve ruined their perfect fasting streak, feel guilty and give up.

This isn’t only a problem in fad diets. This can also be a problem for those tracking macros or counting calories.

Though these are my preferred methods, as it educates the person about calories and food choices. They still can be problematic for some people. If you take a rigid approach, where you tell yourself you must hit 1200 calories per day. What happens when you go over? Most people just think it’s all ruined then end up eating 4000 calories. Or some people will refuse social gatherings or restaurants where they don’t know the calories.

With these kind of issues, you can see why people say diets don’t work.

But just because these things happens, does not mean diets dont work.

A level of flexibility would make these issues far better.

Instead, have a more flexible approach. Tell yourself you’re allowed to have any food you like. You’re allowed to consume as many calories as you want. When you tell yourself this, it takes whatever food you’re dying for off its pedestal.

So, if you’re doing something like Keto, fasting or a Paleo-style diet. Remember they’re just methods to lower your daily calorie intake. So if you break the rules occasionally, nothing bad will happen. Just enjoy the moment and get back on it. Don’t slash’s the other 3 tyres.

if you’re counting calories. Remember the calculator you used to work out how many you need is only an estimate. When you’re tracking the food on Myfitnesspal that also, is only an estimate. If you go over one day it doesn’t matter. Just make sure your weekly average has you in a deficit and you’ll be fine.

Don’t waste your time obsessing over making sure you have the exact amount of protein, carbs or fats. It really doesn’t matter. Just get in enough protein and be somewhat in a deficit.


Another reason people feel like diets don’t work is because they aren’t adhering very well or being consistent.

100% of people who claim to be in a calorie deficit and not lose weight were not in a calorie deficit.

Why is this though? These tend to be the main culprits:

  • Miscalculating foods
  • Not tracking everything we eat (spoonfuls of peanut butter, drinking milk from the carton etc)
  • Binging on the weekend
  • Being impatient

As humans, we’re just not good at being accurate with food intake. We all lie to ourselves, me especially. it’s easy to sneak hundreds of extra calories and take yourself out of your deficit. (5)

Without a strategy, it’s likely you’ll suffer your diet Monday to Thursday. Come Friday to Sunday you eat everything in sight, then repeat the vicious cycle Monday.

Then there’s those who did x diet but got no results. But they only did it for a week or 2. When you’ll need at least 2-3 months to see a significant change.


Another reason for the claim diets don’t work is due to the hunger which is endured. There’s no denying when you diet, you’re going to be hungrier. It’s your bodies way of trying to keep you alive.

But despite the extra hunger, people have still managed to diet successfully and lose weight. Some even keeping it off.

Though you will be hungrier, there are things you can do offset that hunger:

  • Focus on less energy-dense food (high volume foods)
  • High protein diet
  • High fibre diet
  • Cut out drinks with sugar
  • Eat-in a larger calorie deficit (sounds crazy but hear me out)
  • Take regular implemented diet breaks

I’m not saying these will make dieting super easy. But they have been shown to be things people that are successful with their diets do.

There is evidence some people are predisposed to be being slightly heavier. This is not so much because your metabolism is slow, that’s pretty much a myth. But some people are predisposed to have a larger drive to eat more. Whereas some people naturally just move around less. (6,7)

However, that doesn’t mean you should listen to people who say diets don’t work and just give up. It just means you need to accept the cards you’re dealt and work a little harder than others.

As for movement, I’d advise getting a pedometer and tracking your steps. Just find ways to move around a little more. (8)

Habits of the 20%

What is those 20% do which means they keep off the weight?

Well according to The American Journal of Clinical Nutrition, people that have lost over 10% of their body weight and kept it off, tend to include these habits:

  • Exercising for an hour a day
  • Lower calorie, lower fat diet
  • Eat breakfast regularly
  • Self monitor their weight
  • Eat similarly over the week and weekend
  • Nipping relapses in the bud


Evidence does show, those who exercise regularly after weight loss are more likely to keep weight off. Its been shown after weight loss, you burn slightly fewer calories than someone who was naturally at your new weight. Therefore if you can increase your energy expenditure by a tiny amount, that may be what’s needed to prevent a small caloric surplus eventually leading to weight regain over time.

Eating less fat and fewer caloires sounds obvious, but there are ways it can be easier. Not choosing drinks with sugar, for example. Not needlessly consuming alcohol etc. Yes eating fat doesnt make you fat. But fat contains 9 calories per gram, which is double carbs and protein. Therefore by eating foods high in fat, you are more likely to eat more calories, whilst eating less volume, therefore you may feel less full. This is not saying shouldnt eat fat, but be mindful. For instance foods, like olive oil and nuts and fat on meat can easily rack up to 100’s of calories.

Evidence shows those that who eat breakfast tend to keep weight off. Like the others, this doesn’t apply to everyone. Some people find skipping breakfast an easy way to save calories for later. Others feel they overeat if they skip breakfast. Both points are valid. If you find yourself getting super hungry in the day, maybe incorporating a high protein, high fibre breakfast, will help you stay full later in the day. That’s for you to try out.

People that keep weight off are known for self-monitoring. This could be using the scales, taking measurements or just making sure their clothes fit. this makes sense if your account and see a slight change, you can quickly change it. If you bury your head in the sand, before you know it, you could be back to where you were.

Eating similarly is something I mentioned earlier. If you’re starving yourself during the week and blowing out on the weekend. Not only are you at risk of overdoing things, but you also can mess with yourself mentally. You make yourself feel bad on the weekend, then you may get to the week and just give up. Applying some consistency is helpful.

Finally like I mentioned with self-monitoring if you see something going wrong, addressing it, is the best thing you can do. It’s like how we purposely choose not to check our bank account or do our taxes last minute. Trust me, sort things ASAP.

Final thoughts

It’s not a case that diets don’t work. They do. All diets work. What people struggle with is finding a diet, that works for them and suits their lifestyle. Or a diet, they can do, where they can easily transition into maintaining that weight loss without going crazy.

If we spent just as smuch, if not more time, on helping people find a way to maintain that lost weight, wed definitely be moving in the right direction.

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