Debunking Diets: Why Fad Diets Don’t Work

  Mar 18, 2021  |  #Intuitive Eating

Let’s talk about diets, shall we?

We know that diets don’t work long term. However, I want to acknowledge that many people go on and off diets and it’s no fault of their own. 

That’s what most of us KNOW and think is normal in the culture we live in. Modern-day culture is obsessed with losing weight.

Did you know that the diet industry is valued at $72.2 billion and is still growing!? Dieters throw insane amounts of money at the possibility of losing a couple of pounds, only for 97% of them to regain all of the weight they lost, plus some.

Social media graphic with text about dieting taking up mental energy and space

Still, it seems that for every failed diet, there are several more to try, all vowing that they’ll be more successful than the last.

So, the Bucket List Tummy team has compiled nine of the most popular modern-day fad diets and reasons why fad diets are harmful and can’t come through on their promises.

What is a Fad Diet?

A fad diet is one that promotes quick, effortless results. Of course, these results aren’t maintainable for the large majority of the population. 

Characteristics of fad diets also promote quick fixes, magic weight loss, and usually cuts out one or more foods or food groups. 

Most fad diets fail because they are not maintainable and we aren’t meant to follow them long term. 

Social media graphic about skipping out on food groups | Bucket List Tummy

There are also several dangers of fad diets, which we will discuss throughout this post, some of which include:

  • nutrient deficiencies
  • side effects like a loss of hair, irregular menstruation, bone weakening
  • improper growth
  • weight gain
  • tarnished hunger and fullness cues
  • poor body image
  • poor relationship with food
  • weight cycling, which increases the risk of insulin resistance and other chronic disease

1. Low Carb Diets

Bread. Pasta. Cereal. Even bananas—say goodbye to all of them, if you’re saying hello to the low-carb diet. The diet minimizes the intake of arguably the most glorious macronutrient, all for the goal of lowering insulin levels in order to prevent the creation of body fat.

Many dieters note that decreasing carbs and increasing the intake of protein and fats make them feel fuller for longer.

bagel with peanut butter and banana

The most extreme, structured and established low-carb diets are the Atkins Diet and the South Beach Diet—you’ve probably heard of one, if not both, of them.

Their popularity skyrocketed in the age of low-fat diets, also known as the early 2000s, because they allowed dieters to eat “forbidden foods” like bacon and hamburgers. Both diets decrease carbohydrate intake until finally reaching a maintenance phase of eating low carb permanently.

At first glance, the science behind low carb doesn’t seem completely outlandish. When you eat carbohydrates, your pancreas secretes insulin to take up glucose and either uses it as energy or—you guessed it—store it as fat.

So, if you’re not eating carbs, your body can’t store them as fat, right?

Wrong. Through a variety of complex chemical reactions, the body can store protein or dietary fats as fat, too. But let’s back up a few steps and address the glaring issue here: carbs are the body’s preferred fuel source and shouldn’t be viewed as evil, fat-producing agents.

holding up bagel sandwich against brick wall

Side Effects of Low Carb Diets:

In fact, most dieters complain of:

  • headaches
  • fatigue
  • brain fog
  • mood swings
  • and more

This is the body begging you for energy, or in other words, glucose.

On top of that, a large percentage of the weight lost on a low-carb diet is water weight. Glycogen stores, which are essentially stockpiled glucose, stabilize blood sugar between meals and provide quick energy during activity.

For every gram of glycogen stored, the body retains 3 grams of water alongside it. When you switch to low carb, the body burns through its glycogen stores before reverting to other fuel sources, which means the initial burst of weight loss is almost all water weight, not fat loss.

pitcher of water with glass of water

Plus, carbs have a plethora of nutritional benefits that the diet industry conveniently ignores.

Benefits of Carbohydrates:

  • Whole grains protect against metabolic syndrome, type 2 diabetes, heart disease, cancer and stroke.
  • Fruits and vegetables (which, yes, are carbs) defend against heart disease, stroke and some cancers while also providing fiber and a plethora of micronutrients.
  • Legumes, like beans and lentils, supply soluble fiber alongside protein and B vitamins to fend off heart disease and cancer. 

2. The Ketogenic Diet

The ketogenic diet, or “keto,” is often confused with low carb. Keto is one form of a low-carb diet, but it takes the concept a step further.

In keto, the goal is to eat adequate fat so the body enters ketosis, or a state of relying on ketone bodies, which are made from fats, for energy. In theory, the body will revert to burning stored fat, resulting in weight loss.

High Fat Foods for Runners (fish, eggs, nuts, cheese)

More than any other fad diet, using keto for weight loss is entirely off-base.

Keto was originally designed to treat epilepsy in children who don’t respond to seizure medications. Due to its extreme nature and remedial purpose, patients normally start the ketogenic diet under hospital supervision.

In the keto diet, an individual obtains about 75% of their calories from fats, 20% from protein, and only 5% from carbohydrates. The heavy emphasis on fats can easily result in macro- and micronutrient deficiencies.

For example, it’s pretty much guaranteed that the dieter will be carbohydrate-deficient, resulting in “keto flu,” or flu-like symptoms that also accompany other low-carb diets.

Further, eating anywhere near the recommended daily intake of fruits and vegetables would take the body out of ketosis, or cause the body to use glucose for energy again, so most individuals on keto are severely lacking micronutrients.

fresh produce next to black cutting board

Now that we’ve covered the physical ramifications of the Ketogenic Diet, the social drawbacks aren’t any better. Beyond the “keto flu,” having to eat such a strict, niche diet will limit social situations involving food.

I mean, what’s a birthday without a sugar-loaded cake? Definitely not my kind of party.

3. Vegan Diet

The vegan diet is truly a lifestyle for many, especially those who follow it for ethical reasons. 

There are a variety of wonderful, respectable reasons to go vegan—environmental sustainability, saving the animals, experimenting with new culinary techniques, even heart health.

Still, many people figure that initially switching to a vegan diet will shave off the pounds because plant-based foods tend to be less calorically-dense and don’t cause the “inflammation” that animal products do.

Veggie hash in skillet with raw kale | Bucket List Tummy

Going vegan doesn’t change the number of calories the body needs, though. Regardless of where it’s coming from, the body requires significant energy even for its basic functions.

Overriding that demand for the purpose of weight loss is rarely, if ever, a good idea. Veganism may make it easier to cut calories for some (although technically, most oreos are vegan), but eliminating entire food groups in order to do so is restriction.

More than that, major restriction can lead to yo-yo dieting, which is incontrovertibly linked to type 2 diabetes and heart disease.

Approaching a plant-based diet well is possible, though, it just requires thoughtfulness and effort. If you’re not willing to put in preparation, it’s easy to become nutrient deficient.

clear bowl with brussel sprouts, carrots and parsnips

Nutrients of Concern for Vegans:

  • Vitamin B12, which supports cell health and DNA replication, is only found naturally in animal products. Conscientious vegans should either take a supplement or incorporate B12-fortified foods like dairy alternative milks or plant milk, breakfast cereals and soy products.
  • Vegans need to be careful about competing nutrients, like phytates and fiber, that may limit nutrient absorption (like iron, calcium)
  • Protein deficiency is another major concern for vegans. Dietary proteins are composed of a variety of amino acids, some of which are essential, meaning they cannot be synthesized by the body and therefore must be obtained through the diet.
  • Almost all complete proteins, or proteins that contain all 20+ amino acids, are animal products, whereas most plant-based proteins lack multiple amino acids. Because of this, vegans must take extra care to eat complementary proteins. In other words, they must pair two or more proteins together that contain the amino acids the others lack.

As you can imagine, repeating this process daily takes knowledge and creativity, so while veganism can be executed in a healthy manner, it isn’t for the faint of heart.

4. The Paleo Diet/Whole 30

The paleo diet and Whole 30 are insanely popular in the fitness community. While the two have minor differences (like Whole 30 lasts for one month while paleo lasts indefinitely), they operate on the same premise: cut out “junk foods” that weren’t available during paleolithic ties and you’ll magically drop the pounds… at the cost of eliminating sugar, grains, legumes, dairy and any processed foods.

chopping vegetables on cutting board for meal prep | Bucket List Tummy

Like I said previously about plant-based diets, cutting out food groups for no legitimate reason usually backfires in that it can create food rules or is not maintainable, especially if they are foods that you like.

By eliminating grains, legumes and dairy, you’re putting at a risk for calcium, Vitamin D, potassium and fiber deficiencies.

And remember that yo-yo dieting I just mentioned? It’s a likely possibility here, too.

More so, paleo and Whole 30 are built on food rules and restrictions. Even if a month on the diet helps you lose a little bit of weight, it labels foods as “good” and “bad.” Namely, vegetables and lean meats are “good,” and everything else will make you gain x amount of pounds overnight.

These rules can cause you to spiral into disordered eating and may take years to unlearn, which plainly isn’t worth it.

Holding Intuitive Eating book

5. Juice Cleanses

I have a mouthful of things to say about juice cleanses. Most cleanses claim that ingesting such a high concentration of micronutrients in liquid form rids the body of toxins and harmful bacteria.

But really, it’s all just an excuse to eat too few calories for a period of time. 

Even if your intentions in doing a cleanse are pure, it is completely unnecessary—believe it or not, your body is actually designed to detoxify itself.

The digestive system, respiratory tract, immune system and skin all have filters to prevent contamination. Toxins that bypass these filters are neutralized by the liver and eliminated in urine.

clear glass with green juice and straw

Furthermore, relying on juices can drastically ruin your relationship with food. A small qualitative pilot study found that there is a potential relationship between juice cleanse diets and eating disorders.

Ironically, the best things you can do to support your built-in cleansing system are hydrate, eat enough and obtain enough nutrients.

Side Effects of Juice Cleanses

  • Juice cleanses wipe out the healthy bacteria in the gut, which directly impairs detoxification and depletes electrolytes, resulting in dehydration.
  • The severely limited caloric intake causes weakness, loss of muscle mass and decreased metabolism.
  • Juicing removes the fiber that accompanies whole fruits and vegetables, leaving only sugar, which can produce blood sugar spikes.

Long story short, juice cleanses offer no benefits. Run in the opposite direction.

6. The Cabbage Soup Diet

If you haven’t heard of the Cabbage Soup Diet… yes, it’s a real thing.

The diet orders eating an ungodly amount of fat-free, homemade cabbage soup plus a few other foods like beef, vegetables and skim milk for a week. The creators of the diet claim that following this prescription can make you lose up to 10 pounds in one week.

overhead photo of bowl of cabbage soup

To translate, eating such high volume, low calorie foods is just another way to put the body in an excessive calorie deficit.

As we’ve talked about, a large calorie deficit poses a significant potential for nutrient deficiency. In this specific diet, individuals are likely not getting enough protein. This escalates muscle loss, which, combined with the calorie deficit, can lower metabolic rate after as few as 3 days on the diet.

Plus, only about 34% of the weight lost on the diet is from fat—the other 66% is from water and muscle mass, so a majority of the weight will be regained as soon as normal eating starts again.

While we’re being candid, eating that much cabbage can cause some major GI issues. It’s high in fiber, so excessive intake can lead to cramping. Plus, the diet is notably low in fat, which can inhibit gallbladder function.

7. The Grapefruit Diet

I’m probably a bigger fan of grapefruit than the average individual, but eating grapefruit at every meal for over a week sounds like torture, even to me.

The Grapefruit Diet claims that grapefruits have “magic fat-burning enzymes” that will help you lose up to 10 pounds in 12 days. When executed, it instructs dieters to eat a protein-rich diet that incorporates grapefruit or grapefruit juice at each meal.

Let’s clear one thing up: grapefruits do not have magic fat-burning enzymes. They’re nutrient-dense and low calorie, but these miracle enzymes simply don’t exist. That’s all marketing. 

grapefruit next to sliced grapefruit

Because some versions of the diet limit individuals to only 800 calories per day, the Grapefruit Diet can show some short-term weight loss, similar to the Cabbage Soup Diet.

But also like the Cabbage Soup Diet, this caloric restriction can cause fatigue, muscle loss and even a decrease in metabolic rate. The side effects of restriction always come back to get us because our bodies are smart!

8. Intermittent Fasting

I’ve heard a couple of different theories behind intermittent fasting. Some people swear that, if you limit your eating to certain hours, you’ll eat less.

Others claim that the body enters ketosis during the fasting hours, and the low insulin-to-glucagon prevents fat synthesis. Regardless of which theory holds more weight, intermittent fasting can be dangerous to mess with.

table for dinner at 204 north

The body wasn’t made to go 16-24 hours without food, let alone do so regularly. More than most other diets, intermittent fasting alters hormone levels.

For example, it increases cortisol, which escalates stress, causes muscle loss, promotes fat storage and even interferes with sleep

Intermittent fasting also disrupts hypothalamic rhythms, which can throw off ovulation and stop menstruation. These hormonal imbalances have a ripple effect, also negatively affecting metabolism and mood.

As with other diets, such extreme restriction can result in rebound overeating, which often leads to yo-yo dieting.

On top of that, intermittent fasting forces you to unlearn natural hunger cues, which directly opposes eating intuitively and keeps you from listening to your body’s needs.

empty plate with pie crumbs left

9. If It Fits Your Macros (IIFYM)

A calorie is a calorie, right? Ask anyone who follows If It Fits Your Macros (IIFYM, for short), and they’d say so. They’d tell you that, as long as you weigh your food and track your macros to the gram, you’ll meet your physique goals.

Even though it now masquerades under a different name, this was also the postulation behind the early ‘60s diet program, Weight Watchers.

First of all, the “calories in equal calories out” mindset has some glaring flaws. Calorie needs fluctuate daily depending on changing mental and physical demands, so assuming that you can eat the exact same composition of food every day is not really practical.

IIFYM can also create an obsession with weighing, measuring and tracking food, and no one wants to live like that.

food scale with food in it

The thermic effect of feeding, or TEF, refers to the energy spent digesting food, and it’s actually a huge part of the equation.

Protein requires about 20-30% of its calories just to be digested, whereas fat only requires 2-3%. Because what you eat affects how much energy your body uses in digestion, you’ll never know exactly how many calories your body burns (and consequently needs).

But that’s what hunger cues are for—your body’s way of telling you when it needs energy and what type. Counting macros won’t figure that out for you.

You are not a machine that operates on autopilot. 

girl at her laptop in kitchen

All of these fad diets have one thing in common: they aren’t worth it.

Your body is smart, and if you try to force it to be any size other than the one it’s genetically predisposed to be, something will give. This quick video on set point theory describes it perfectly. 

Hopefully, you now better understand some of the harmful effects of fad diets. 

list of fad diets

For more resources on defying diet culture, you can check out some of these posts:

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