The Ultimate Guide To The Most Popular Fitness Diets

You might have asked yourself: "What's the best diet to follow?"

First of all, what do you want to achieve with the diet?

Do you want to lose fat quickly? Do you want to have the minimum impact on the environment? Do you want to live longer? Do you feel bored and just want to have a topic of conversation with your friends about your super-hyped diet?

Read along, I've got you covered. All of you!

In this post, you will find out what are the most popular fitness diets out there and which one to choose.

Dieting vs Lifestyle

Before starting, we need to make a clear distinction.

Dieting (Or How To Waste Your Time)

A diet can be defined as a temporary change in dietary habits that is aimed at a goal.
Usually it's used to lose fat.

Example: smoothies diet, clensing diet, the Aktins diet, the Zone diet, etc.

They usually suffer of the yo-yo effect. 

After the diet is over, the lost weight is re-gained partially, totally or even more.

Why Does The Yo-Yo Effect Happen?

Simple. When you lose a lot of weight, your metabolism slows down incredibly (especially if you haven't paired the diet with a workout plan).

After the diet you go back to eating the way you were eating before and, since now you are hungry like a wolf, you will be eating calories above your maintenance level, hence you'll get fat again.

That's why, when you diet you should be building muscles. Muscles in fact will increase your metabolism since they require energy to be kept alive and functioning.

This also shows one problem with diets: they are temporary. 

If you can't sustain the diet's food choices in the long term, terminating the diet will simply bring you back where you started.

Lifestyle Won't Make You Fat Again

Which brings us to the topic of lifestyle diet aka way of eating.

The change in food choices that you make to achieve your goal become part of your lifestyle. It's not anymore some weird diet that you don't like or that it is not for you.

It's not "dieting", it's eating.

When you pick a way of eating that drives towards your goal while at the same time being enjoyable, there you have the sweet spot that will make you achieve the goal faster, permanently and without cheating during the process.

Now that we made this distinction, let's see what are the most common diets/way of eating out there and what their main goal is.

The Ketogenic Diet

Its detractors call it the eggs and bacon diet.

Not completely false as most beginners with this diet usually face the problem of not knowing what to eat on this diet and end up eating just eggs and bacon.

For a more complete guide, check my epic guide on the ketogenic diet.

What Is The Ketogenic Diet?​

The ketogenic diet is a very low carb high fat diet (VLCHF) diet in which carbohydrates are severely restricted (up to 50 grams of net carb; fibers do not count towards this number) and plenty of fat is eaten as main energy source. Protein intake is moderate.

By restricting carbohydrates, your body will use fat as energy source. Fat will be converted to ketone bodies which will be used as a substitute for glucose from most of your tissues (even the brain).

This is not dangerous nor unhealthy. Ketones are normally present in our blood during intense exercise and fasting periods (as for instance sleep). The ketogenic diet is actually one of the healthiest diets out there (more below).

The ketosis reached on this diet has not to be confused with the pathological condition called ketoacidosis which might manifest in diabetic people.

For a cookbook, you can check this one.​

Why The Ketogenic Diet Might Suck For You

Some people in the first 2-5 days (some others in the first couple of weeks) might go through a phase called keto flu during which they experience severe lethargy. Nothing to be scared of, it will go away. It's just your body switching from a carbohydrate source of fuel to a fat one.

Without any form of doubt, this diet is pretty restrictive in the foods you can eat and this for some people seems to be a problem, especially when eating out.
Although there are plenty of resources to find delicious keto recipes.

Have a look for instance at some of my keto video-recipes: keto bolognese sauce, keto Italian broccoli&sausage, ketogenic protein bars, keto pizza, keto stuffed zucchini, keto zucchini chips. I even have a video in which I show a full day of eating on the ketogenic diet.

If you are an endurance athlete, you need carbs and the ketogenic diet might not be for you. I would also recommend you to avoid the ketogenic diet if you are susceptible to depression or anxiety and have thyroid problems.

Why The Ketogenic Diet Is Super Healthy

Once you get used to the delicious food choices on the ketogenic diet, you just have benefits to reap from this diet.

For one, if you are on a very strong calorie deficit, this diet has a very powerful hunger suppression effect (ref) even though science still doesn't know why (ref).​

One typical problem of very low caloric diets is to have to reduce fat intake to dangerous levels, impairing the production of sexual hormones. This does not constitute a problem on a ketogenic diet which provides plenty of fat.

Can You Build Muscles On The Ketogenic Diet?

 Many broscientists still swear by the dogma that you need carbs to lift weights and get big. This has been proven wrong time and time again by several studies (in the description of this video you'll find all the scientific references).

If you are cutting, the ketogenic diet is actually perfect since you don't lower your fat intake too much. This will lead to maintaining your testosterone levels hence you'll be able to keep making gainz.

You can find a pretty popular community of bodybuilders on the ketogenic diet, called Ketogains, check them out, they are pretty impressive!

Ketogenic Diet Food List

Macros For A Ketogenic Diet

Let's see how to set your macros on the ketogenic diet.​

1. Set your protein intake to 1.8 g/kg of bodyweight (or 0.8 g/lb bodyweight).
   Everything above this number will be converted to glucose through a biochemical process called gluconeogenesis. Therefore if you eat more than that, calculate half of the protein surplus towards your carbs intake.​
2. Set carbs intake to max 50 g/day.
3. Fill up the rest with fat.

Summary Ketogenic Diet

>> Read more: The Most Epic Guide On The Ketogenic Diet On The Entire Internet

The Paleo/Primal Diet

What Is The Paleo/Primal Diet?

The premise of this diet is that we have all these diseases and widespread obesity because we grew apart from our ancestral way of eating. The way the paleolithic men used to eat is the way we are supposed to eat, according to the proponents of the paleo/primal diet.

The Paleo diet prescribes high protein meals with low carb intake (especially starchy carbs as rice and potatoes and grains) and plenty of veggies. It limits fat intake and eliminates any form of sugar, gluten and processed foods. Food has to be as closest as possible to its natural form.

The Primal diet is based on the Paleo diet with more relaxed restrictions. In fact, dairy and saturated fat are allowed on this diet.

Not necessarily a Paleo/Primal diet is a low-carb diet. If you are interested in weight loss and you don't want to track your calories then try to limit the intake of carbohydrates (e.g. fewer fruits and potatoes).

The invention of agriculture, they say, is when thing started going bad. Therefore all products as grains and legumes (which were basically created with agriculture) are banned in this way of eating.

This is the closest diet there is to the one I use. My diet is loosely based on the Primal diet guidelines and you can check out the foods I'm actually eating in this video.

Here you can find a cookbook to start with: Paleo Cookbooks - Complete Paleo Recipe Guide To Healthy Eating.​

Problems With The Paleo/Primal Diet

Unfortunately for its proponents, we ate grains and legumes as paleolithic people, recently found out. Furthermore, the vegetables and fruits we eat today are a far cry from the ones our ancestors might have encountered. For a more comprehensive rebuttal of most of the Paleo claims, Alan Aragon has a comprehensive presentation.

Even though the premises on which the paleo/primal diet are based are flawed, these diets still constitute a healthy way of eating (ref) if one is careful of not falling under extremisms.

Health Benefits Associated With Paleo Diet

Being this diet a pretty "recent" invention (which is pretty ironic for a diet based on the paleolithic ​way of eating), research lags a little bit behind compared to the ketogenic diet.

The few studies available, though, correlate a Paleo way of eating with several health benefits.

• ​Correlation with decreased LDL cholesterol and triglycerides. (even though in some studies HDL decreased too)
• Correlation with lower food intake and weight loss.
• Seem to lead to improvements in insulin sensitivity and glycemic control.

It's worth mentioning that these studies are made on a small scale and many are uncontrolled. Comparison of the studies can be found in more detail here.

Paleo/Primal Food List

Macros Paleo Diet

The Paleo/Primal diet is a diet indicated for ad libitum dieting which means a diet in which you don't control your calories intake.

If you want to track them, just set your protein intake to 1.8 g/kg of body weight (0.8 g/lb of body weight). The ratio of carbs/fat doesn't matter for muscle building (ref, ref, ref).

Summary Paleo/Primal Diet

IIFYM

What Is IIFYM?

If It Fits Your Macros is a diet or lifestyle originally meant as a joke on the bodybuilding.com forum.

Whenever people were asking if they could eat a certain food to bulk or a cut, more expert members were replying "if it fits your macros". Since it became annoying that everyone was asking that, it quickly became IIFYM.

Nobody thought that the whole thing would have evolved in an actual lifestyle and an excuse for people to shovel down tons of junk food under the blessing of macros fitting.

In brief, this diet enables to eat whatever food you want (yes, even junk food) as long as it fits your macros. It means that as long as you hit your daily caloric target at the end of the day, it's fine. And there is even the cookbook with IIFYM recipes (lol).

IIFYM Food List

Problems With IIFYM

This diet treats food as just energy, forgetting that the food with eat is much much more. It's easy on this diet to eat a lot of processed foods devoid of nutrients as minerals and vitamins.

Also, nutrient timing is not taken in account leaving you with a very un-optimized way of eating which can lead to poor health and muscle gains (if you don't know what you are doing).

Check the RIIFYM (Rational IIFYM) for a more optimal version of this diet.

Why IIFYM Might Be Right For You

You can easily get very lean or very muscular on this diet. But it comes with sacrifice on the health side, especially if you are not considerate.

This is literally the YOLO diet.

If you don't care about long-term effects and want to just live in the now, go ahead.

With a little bit of structure, IIFYM can give you incredible results and let you eat whatever you want!

Summary IIFYM

Protein Sparing Modified Fast (PSMF)

Know to very few, this is a very aggressive short-term diet for fat loss.

Be aware that this is a temporary diet and it cannot become a lifestyle.

What Is The Protein Sparing Modified Fast Diet?

On the PSMF diet, you eat only proteins and a minimal amount of other nutrients (carbs and fat) hitting a caloric goal of less than 900 kcal a day. Yes, that little.

This diet reaps the benefits of a fast while limiting the loss of muscle tissue.

In fact, by providing an adequate intake of proteins, vital functions will be maintained without breaking down muscle tissue to derive amino acids from.

​

Supplementation with minerals (sodium, potassium, and calcium), vitamins, and fish oil is fundamental on this diet. Please consult your physician if you're embarking on this diet for more than a few days.

Why PSMF Sucks

On my rest days (when I don't workout) I'm on a PSMF diet and I can tell you this diet fucking sucks. Big time. Though it's really really effective.

Many people go ketogenic on this diet too. Therefore, because carbs are dramatically restricted, a lot of liquids are lost. This poses a risk of dehydration and electrolytes imbalance. This is why supplementing minerals and drinking plenty of water are pivotal.

By eating a very limited amount of foods, it's very easy not to cover your vitamins and fat requirements. Therefore a multi-vitamin is fundamental on this diet as well as fish oil.

Because your fat intake will be very low on this diet, a drop in sex hormones is very likely to happen. Of course this is temporary as once the diet is over, their levels will be re-established to the norm.

​But let's talk about the main reason why this diet sucks.

Hunger.

You're gonna be eating less than 900 kcal a day and you can imagine how hungry you're gonna be. As well with bad mood and grumpiness. 

There are several ways to fight this and some can be found in my free nutrition guide "Eat Like A Human, Look Like A God".​

Supplements to stop hunger can be coffee, chili powder, tea, ephedrine.

Why PSMF Will Get You Lean Fast​

Despite sucking, the protein sparing modified fast diet works.

It's the fastest way to lose a lot of fat and won't take away your muscles (especially if you don't stop working out).

With its very high caloric deficit and it's high protein intake, fat loss is assured at the fastest rate possible while keeping your muscle mass almost intact.​

Protein Sparing Modified Fast Food List

Macros PSMF

For a person working out, here my guidelines to set your macros on a protein sparing modified fast diet

1. Set your protein intake to 1.8 g/kg body weight (0.8 g/kb body weight)​.
2. To get the carb intake, divide the grams of protein from step one by 2.
3. To get the fat intake, divide the grams of protein from step one by 4.

Summary Protein Sparing Modified Fast

The Bulletproof Diet

The mother of the broscientists is always pregnant and there you have Dave Asprey with his (in)famous bulletproof diet.

This diet is a powerful marketing tool to promote the product line​ around the Bulletproof coffee (which is just regular coffee with butter and MCT oil which is sold at twice the normal price).

Based on the Paleo template this diet proposes "biohacking" method "science-based" to increase longevity, mental performance and all the usual crap this guy gets boners talking about.​

What Is The Bulletproof Diet?

This diet has more or less the same food choices of a paleo diet although with more fat and less protein. It also proposes intermittent fasting and a weekly "protein fasting" in which you eat only 15-25 grams of proteins "to help cleanse your inner-cells without muscle loss". Of course he goes on saying that "to keep you fully energized, consume a cup of Bulletproof Coffee in the morning".

If you still made it without laughing so hard and rolling on the floor, you know by now what a bunch of crap this diet is. I'm writing about it just to be exhaustive in this article and warn you about this diet.​

Let's be clear, you are not gonna die on this diet. It's not unhealthy or dangerous.

The claims this diet is based on are completely false and very unscientific.

Even though the author references *some* of his claims with scientific papers these are mostly on rats and mice or if on humans have a very limited sample size.

For some rebuttals debunking the whole Bulletproof diet, check here, here, here and here.​

Check the Paleo or Primal diet if you want a very similar diet to this one.​

The Slow-Carb/4-Hour Body Diet

I love Tim Ferriss, I really do. Sometimes, though, I think he should just focus on talking about productivity and philosophy and leave things he's not expert in, to the experts.

What Is The Slow Carb Diet?​

This diet has also exorbitant claims although it's basic premises are not that wrong.

This is a low carb diet in which grains (rice, barley, oats, quinoa, wheat), starches (pasta, potatoes), fruits and cheese are avoided.

The diet calls for lean protein consumption ​together with legumes and vegetables.

Once a week there is a cheat day in which you can eat the prohibited foods. (How to fuck up everything you gained in one week, by the way).

According to this diet, you should eat a lot of proteins within 30 minutes of waking (?) and eat the same few meals over and over again (which I think is a good thing).

Slow Carb Diet Food List

Why The Slow Carb Diet Sucks​

​The inclusion of legumes, in my opinion, is there to give you some sort of satiety and avoid ketosis which would definitely reduce the compliance.

There is a problem though: not everyone can well tolerate legumes. They can make you (very) gassy and bloated.

Furthermore, if you workout, you should know by now that they contain anti-nutrients as phytic acid that prevent proteins and minerals absorption (soaking, fermenting or sprouting them can help tho).

The claim of starting high in protein is also very dubious.

The biggest problem then is the cheat day. I will write a post about this but let me tell you this. There is nothing magical about cheat days. They will just add up calories, period. If you really want to have results, be disciplined and consistent.

Cheat days will only dramatically slow down your progress.

Why The Slow Carb Is A Good Diet

If you don't want to count your calories and you are fine with eating beans, this diet can be convenient to manage especially when eating out.

Summary Slow-Carb Diet

Carb Backloading

Another bro-diet which claims to be based on science while this being only partially true.

What Is Carb Backloading?​

This diet is based on the faulty idea that insulin is the main driver of fat accumulation. By the way, that is not true.

Therefore this diet is basically a ketogenic diet until after the post-workout in which you slam down A TON of as much refined carbs as possible.

The idea behind is that these carbs will give you a very strong and sharp insulin spike which will promote uptake of amino acids from the muscles.

Not only this is not necessary (proteins by themselves can spike insulin), the amount of carbs proposed is preposterous. 

Ah, in the post-workout window, junk food not only is allowed but encouraged (?).
I see IIFYM people waving their hands.​

Carb Backloading Food List

​Why Carb Backloading Sucks

Giving a freeway for junk food is never a good thing. Also, its obsession for simple refined carbs is total nonsense.

Complex carbs are a no-no on this diet for the reason being that they don't spike the insulin high enough and that they'll keep the insulin high for longer, making you fat (?).

In the book, also, fruit is prohibited mentioning the bullshit about fructose making you fat which is old broscience.

Throughout the book scientific references are made to papers not only not describing the mentioned fact but sometimes even completely denying it.

You can read a debunking on this diet here (I know, it's on the bodybuilding.com forum but it's a valid one).​

What Is Good About Carb Backloading

​The nutrients timing idea behind it is solid as we have seen before. 

Indeed eating most of your carbs at night is beneficial for several health-related parameters although this is fine-tuning your diet, really.

Also, eating most of your calories after working out is a solid concept backed up by science as you can check here.​

Summary Carb Backloading

Which Diet To Choose?

I know, it can be pretty confusing to decide which diet to follow even though I tried my best to give you all the information available and make it as clear and simple as possible.

You don't actually need to follow any diet to start with! You just need to define what your goal is (losing weight? gaining muscles? both?) and decide to which degree are you going to commit.

Are you willing to not have grains? You don't care about long term and want results while enjoying every crappy food available?

These are choices that I cannot help you with.

Look inside your self, my young padawan and there you will find the answer.

If you want to see what my diet looks like and what foods I consider the best to get both the body you dream while staying healthy, then you can check my ebook  "Eat Like A Human, Look Like A God" (click here for the free download).

Let me know in the comments below what your experiences are when it comes to diets and which you liked the best.

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Cover image modified from https://flic.kr/p/qpS4C4 under license CC BY 2.0.