The Science Behind Why Fad Diets Don't Work

It seems like there are two types of people in this world: those who are naturally slim, and those who have to make a concentrated effort to avoid piling on the pounds. 

While this is just an observation, the reality is that some people find it easier to maintain their desired weight than others. A large study by the University of Cambridge confirmed that genetics do indeed play a role here—they work in favor of thin people and against those on the obese end of the scale. 

And if you're one of those who finds it difficult to lose weight and then sustain weight loss, you've probably tried a fad diet or two in your time.

As our knowledge of food, nutrition, and health in general continues to grow, we're learning about the methods that are effective for weight loss—and those that aren't.

It's safe to say that fad diets are in the second category. 

This article will discuss why fad diets don't work, backed by scientific evidence.

What Are Fad Diets? 

Fad diets involve cutting out a lot of foods, with the promise of fast-tracking you to weight loss. 

Thankfully, today's fad diets are at least less poorly-informed than they were several decades ago when everything from grapefruit to cabbage soup was claimed to be a miracle formula for weight loss. 

But still, what makes a fad diet "faddy" in today's world is that it lacks robust scientific evidence to support its claimed benefits. 

A few fad diets you might have heard of include: 

• The Atkins diet
• Whole30
• The paleo diet
• The keto diet

While many people following these diets may have successfully lost weight, they're generally not a sustainable weight loss solution in the long run.

Why Don't Fad Diets Work?

So, why are fad diets not as effective as they're claimed to be?

To start with, they might actually have the complete opposite effect of your intended outcome by altering your hormones so that your body feels hungrier, making you more likely to reach for a calorie-dense food.

Research from 2017 found that eating fewer calories can cause hormonal changes in the body that actually stimulate appetite, increasing cravings for higher-calorie foods.

Some fad diets even cut out entire food groups, which can be very dangerous to health since we need these foods to survive. 

In many cases, fad diets pose their own risks. For instance, a 2021 study on ketogenic diets and chronic disease noted that such diets affect diet quality due to the increased intake of foods linked to chronic disease risk and the reduced intake of foods found to be protective in studies, concluding that their risks may outweigh their benefits. 

Similarly, a review of studies into the effects of the Atkins diet concluded that significant long-term weight loss is an unlikely result of low-carb diets, according to evidence from "numerous studies," and may even lead to serious health problems and nutritional deficiencies. 

In short, fad diets may cause you to lose weight initially, but many carry long-term risks, and you might end up gaining weight due to increased hunger hormones.

The Solution: Healthy, Sustainable Weight Loss

Unfortunately, while it would be great if you could follow a diet that helped you to lose weight within a matter of weeks and then keep it off for life, there's very little evidence to suggest that this can ever be achieved by following a fad diet. 

The only way to achieve healthy, sustainable weight loss is to change your mindset around food (and exercise if you're currently a self-proclaimed couch potato). 

There's also evidence that weight loss medication can help curb the cravings for calorie-dense foods by making you feel fuller for longer, so it may be helpful for you to supplement your diet and lifestyle changes with medication recommended by your doctor. 

Losing weight effectively doesn't have to involve yo-yo dieting for the rest of your life. Next time you're tempted by a fad diet, remind yourself that if it sounds too good to be true, it probably is. 

Instead, eat healthy, balanced, satiating meals throughout the day, focus on loading your plate with healthy veggies, get moving, and—most importantly—still allow yourself to eat the foods you love.