Why The Mono Diet Is Bulls**t

I had a friend who once tried something called “The Cabbage Soup Diet”.

As the name suggests, it involved eating nothing but cabbage soup.

She was depressed.

She used to look at my lunch the same way my dog does, drool forming in the side of her mouth as she sat there thinking of what might’ve been.

When I asked her why she put herself through such a harsh diet, her response broke my heart in real-time:

“Because I’ll do anything.”

Imagine that, for a moment.

Imagine being so lost, so unhappy about your shape, that you’re willing to subject yourself to utter torture.

Turns out, she’s not alone.

As I researched for this piece, I uncovered a whole range of these style of diet plans.

It’s called The Mono Diet, and it’s based around the idea of eating one single type of food (and nothing else) to lose weight.

And today, it’s gonna get wrecked.

I’m going to show you why the mono diet (any of them, take your pick!) isn’t the best way to lose weight and why you should stay clear of this dark corner of the health and fitness industry.

This is not a ‘Nice Russ’ article, where I’m all encouraging and “you got this”…

This is an old-school Russ article, where I rip something to pieces because it deserves to be ripped to f**king pieces.

Strap in…

If you enjoy this read, please drop a like on it at the end.

What Is A Single Food Diet?

The concept of a single food diet is simple.

Eat one single food.

That’s it.

In a world where many are a bit lost with nutrition, I am not surprised that quite a few people are attracted to the simplicity of a diet that just says “eat this, nothing else, job done.”

I’m saddened that there are people out there who will package up some bulls**t “miracle system”, plop a trendy name on it, and tell customers to do something downright dangerous rather than educate them on how to eat properly to lose weight and keep it off.

Because money.

The cabbage soup diet is the tip of the iceberg.

F**k. I’ll be genuinely surprised if there’s not an iceberg diet.

One mono meal plan suggests living on carrots. Another promotes the idea of eating only Mars Bars.There’s even the milk diet – which was created by two doctors, no less.

What a f**king disgrace.

And then there’s Freelee a.k.a. the banana girl, who was all the rage a couple of years ago for her mad diet of 50 bananas per day.

Are people really this desperate to drop a few pounds?


Of course they are.

Proof can be seen by the fact that the aforementioned banana girl’s e-book sold 3000 copies in 24 hours.

Let’s not even talk about the potential Type 2 diabetes risks involved in that…

Because perhaps the worst thing about these gimmicks is that there’s a mentality of the public being suckers, and if they’re willing to fall for it, then they deserve to be robbed of their cash in search of the holy grail.

That’s not how health and fitness should work.

(Imagine if your mechanic sold you a carburetor instead of a gearstick and then had the nerve to say it was your fault for not realizing what he was doing.)

It is not the public’s job to be clued-up on nutrition before they go online searching for help trying to lose weight.

It is your job as a health professional (personal trainer, nutritionist, dietitian, even just a social media influencer in the fitness space) to provide quality information so that you don’t do a motherf**ker some serious harm!

You are f**king responsible.


Why The Mono Diet Doesn’t Work

There are two primary reasons why The Mono Diet doesn’t work.

They are:

  1. It’s nutritionally poor
  2. It’s unsustainable

In terms of sheer weight loss, all we really need to worry about is calories in versus calories out.

This has been proven time and time again. (1, 2, 3, 4, 5, 6)

So, in theory, if you ate nothing but Mars Bars for the rest of the month and managed to stay in a calorie deficit, you would continue to lose weight.

This is not witchcraft, nor is it new science.

But you’d also feel about as healthy as a lard flavoured pizza, due to the lack of protein and fat in your diet. Plus, your skin would break out in spots, your hair would feel awful (well, not mine as I’m bald AF), and your energy levels would be suffering due to a severe lack of vitamins and minerals.

If you lift weights, and therefore require a higher protein intake, then the problems really begin to add up.

You’re burning muscle, and your metabolism is slowing as a result (which will make it easy to regain weight, and much more difficult to lose it again in the future).

Simply put, you’ll be running your damn body into the ground.

Back in the olden days (and I don’t mean the 1980’s, like my kids class the olden days, I mean the real olden days) sailors used to get scurvy by following an ultra-restrictive diet of chicken and rice for months while away at sea because they were missing out on crucial nutrients due to the lack of variety in their daily diet.

And now we have people voluntarily doing it.



The second point is just as important, though.

If your diet is not sustainable into the long-term, then you can forget about achieving long-term results with it.

Here’s an interesting fact: over 85% of dieters regain the weight they lost because they were unable to keep up the lifestyle which helped them lose the weight in the first place.


Basically, the moment you crash off a crash diet (and you will, because the clue is in the name) you will end up back at square one.

But we all fall for these quick fixes from time to time.

Because they (the people who formulate and sell them) use manipulative marketing to prey on people’s insecurities by offering a seemingly easy solution to a problem that is often very complex.

It promotes the idea that you shouldn’t just lose weight, you should punish yourself every step of the way for allowing yourself to get so fat in the first place.

Shame on you.

And nobody is safe.

Fruitarianism (a diet where people must limit their energy sources to only fruit) famously hospitalized television star Ashton Kutcher in 2013 after he used the diet to prepare for his role in a biopic of Apple founder Steve Jobs.

Hollywood superstar Matt Damon also admitted that he once ate nothing but chicken breast in a desperate bid to lean down for a movie role.

Matt Damon chicken breast diet

Matt Damon at just 139lbs.

The Best Diet Is The One You Can Stick To

These crazy fad diets do not promote a healthy relationship with food.

In fact, they do not promote a healthy lifestyle at all.

The worst part is they are often aimed at people who have enough s**t going on in their lives to begin with – a history of troubles with weight loss, stress, and a lack of understanding about proper nutrition.

Mono meal plans often go hand-in-hand with food scaremongering, whereby a certain food group (i.e. carbs or fat) or even an individual food itself (bread, sugar – ironic given the number of fruit-based mono diets out there) is scapegoated as the number 1 reason you cannot lose weight.

What utter bulls**t.

They’re hoping you don’t look for the science.

So allow me to show it to you.

A study published in the American Journal of Clinical Nutrition compared the effects of several isocaloric diets made up of 15% protein, 15%-85% carbohydrates and 0%-70% fat to see whether they could manipulate weight loss despite keeping overall calories the same.

So we had groups going low carb/high fat, moderate carb/moderate fat, and finally high carb/low fat.

They found no difference in results, and concluded that overall caloric restriction determines weight loss, not macronutrient ratios. (1)

This suggests that as long as you are getting enough protein to support lean muscle growth, you can experiment with your diet and build something that a) works for you, and b) you can stick to, while still achieving results.


This was supported by further research from a team at the University of Minnesota in 2005 which concluded that when calories and protein are controlled, there are no significant differences (0.1kg) in weight loss regardless of the make-up of other macronutrients. (5)


A year later, another new study published in the American Journal of Clinical Nutrition also concluded that when calories and protein are controlled, you can go higher in carbs and lower in fat, or vice versa, and still lose the same amount of weight. (6)


Let’s put all of this aside earlier research which compared the effects of a balanced and varied diet versus a rigid meal plan, and clearly showed that rigid dieting strategies (but not flexible dieting strategies) led to greater cases of eating disorder symptoms, mood swings and excessive body/shape issues. (7)

The bottom line is stop punishing yourself.

It’s not necessary.

There is also a popular myth that a Mono Diet will reduce bloating (a deal-sealer for many people!) because “eating only one food makes it easier for the body to digest.”

There is no scientific data to support that claim. It is literally made up.

Practitioners of The Mono Diet will try to woo you with talk about the so-called “magic” in their system.

But all you are really doing is restricting overall calories to lose weight (that’s it). The bad news is you’re simultaneously eliminating crucial macronutrients (protein, carbohydrates or fat) and missing out on vital micronutrients (vitamins and minerals) that your body needs in order to function at 100%.

So there you have it!

The best diet is the one you can stick to. Even the NHS agree with me.

The Mono Diet is the first step to an eating disorder.

The next time one of your friends tackles a single food diet (whether it’s The Mono Diet, Cabbage Soup Diet, or any other mono meal plan of similar setup) feel free to educate them on the fact that, despite what they believe, they’re not only eating one single food.

Because they’re also ingesting a whole load of marketing bulls**t.

the mono diet weight loss


  1. Leibel, R.L., et al. Energy intake required to maintain body weight is not affected by wide variation in diet composition. Am J Clin Nutr. (1992)
  2. Golay, A., et al. Similar weight loss with low- or high-carbohydrate diets. Am J Clin Nutr. (1996)
  3. Golay, A., et al. Weight-loss with low or high carbohydrate diet. Int J Obes Relat Metab Disord. (1996)
  4. Luscombe-Marsh, N. D., et al. Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids. Am J Clin Nutr. (2005)
  5. Raatz, S. K., et al. Reduced Glycemic Index and Glycemic Load Diets Do Not Increase the Effects of Energy Restriction on Weight Loss and Insulin Sensitivity in Obese Men and Women. J Nut. (2005)
  6. Johnston, C. S., et al. Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. Am J Clin Nutr. 2006 May;83(5):1055-61.
  7. Stewart, T. M., et al. Rigid vs. flexible dieting: association with eating disorder symptoms in nonobese women. Appetite. 2002 Feb;38(1):39-44.

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