19 Reasons Why Diets Fail: What To Look Out For

  • By: Tony Miller
  • Time to read: 10 min.

Why Diets Fail

The harsh reality is that many diets fail to deliver the promised results. In this article, we will delve into the reasons why diets fail.

We also cover the underlying principles of weight loss that every successful diet should incorporate.


How Diets Work: The Crucial Principle of Energy Balance

At the core of any effective diet lies the principle of energy balance, often summarized as “calories in, calories out.”

To shed excess pounds, you need to create an energy deficit, meaning you must consume fewer calories than your body expends.

Energy balance

These articles can be helpful in understanding this – Energy Balance For Weight Loss

CICO For Fat Loss

This principle is the foundation upon which all weight loss diets are built.

Food is energy, and the energy is measured in calories (or Kilojoules.)

Let’s take a closer look at why this principle is so vital:

  • Calories In: This refers to the number of calories you consume through the food and beverages you ingest. An effective diet should help you control and reduce your calorie intake.
  • Calories Out: This encompasses the calories your body burns through various processes, including basal metabolic rate (the energy required to maintain basic bodily functions), physical activity, and the thermic effect of food (energy expended during digestion).

A successful diet should decrease your calories consumed. (And perhaps even promote and increase your calorie expenditure through exercise.)

By understanding and manipulating this energy balance equation, diets aim to promote weight loss.

However, it’s important to recognize that the devil is in the details, and this is where many diets falter.


Common Reasons Why Diets Fail

Baked Cod with Lemon and Herbs

We know for any diet to work, it needs to create an energy deficit.

So, if the diet does create a negative energy balance it will work, but why does it fail?

A lot of times it is not the diet as such, but more accurately why the person didn’t or couldn’t continue to follow the diet plan. After all, we are human.

Here are reasons why diets fail:

  1. Too Complicated

Diets that involve very complex meal plans, like where you have to eat only certain food groups, or mix that with this, etc. Overly detailed food restrictions can quickly become overwhelming.

People often give up because they find it hard to follow such complicated weight loss rules.


  1. Too Hard

Excessively difficult diets that demand extreme willpower and self-control are challenging to sustain in the long run.

The more challenging a diet is, the more likely it is to fail.


  1. Too Restrictive with Foods

Carbs for weight loss

When diets eliminate entire food groups or severely restrict certain types of foods, it can lead to cravings and feelings of deprivation.

As an example, diets that limit carbohydrates. But carbs are normally tasty and a big part of foods that are commonly available and popular. So, if you take this macronutrient away, you make it difficult to stick to the plan.

(Macronutrients are: 1. Protein. 2. Carbohydrates. 3. Fats. There are 4 calories per 1 gram of carbohydrates. Protein also has 4 calories per 1 gram. Fat has 9 calories per 1 gram.)

Diet Tip – Carbs are not the enemy and can be eaten in moderation as part of any healthy balanced meal plan.

Chose wholegrain carbs for filling fiber.

Reduce you overall calories by reducing portion sizes. Remember it’s generally not the bread, but the spread that will load up your calories.


  1. Underestimating Calories Consumed

One of the most common dieting pitfalls is underestimating the number of calories consumed.

This often occurs when people don’t accurately measure portion sizes or fail to account for hidden calories in sauces and condiments.

Drinks like energy drinks, pre-workout drinks, alcohol, sodas can add up the calories as much as a meal.

You might find this article helpful – Bad Habits For Weight Loss


  1. Over Estimating Activity and Calories Burned

Exercise for fat loss

Over estimating the calories burned through exercise is another common mistake. This can lead to a false sense of security, as people may believe they can eat more than they actually should.

Calculating calories out, or energy burned is very hard to do accurately.

Tip – Still do exercise, but don’t worry about tracking calories out. If you want to track calories, just focus on tracking calories consumed.


  1. Too Low Calorie, and You Have No Energy

Extremely low-calorie diets can leave you feeling fatigued and irritable, making it challenging to maintain day-to-day activities and exercise routines.

Try doing a 600 calorie a day plan and you will have no energy after a few days? – We don’t mean that literarily. It is also unhealthy.

These diets aren’t sustainable and often backfire as you can have intense cravings and binges.


  1. The Diet is Boring and Bland

Diets that lack variety and flavor are often abandoned in favor of tastier, more enjoyable options like junk food.

How long can you do a soup diet for? Or just have one item like grapefruit or celery?

Boring diets are hard to follow long term, little known for more than a few days.

You might be interested in this article – 51 High Protein Dinner Ideas For Weight Loss


  1. Junk Food Tastes Good, So It’s Easy to Consume Too Many Calories


Let’s be honest, a lot of junk food and takeaway meals taste delicious. (It’s designed that way to sell more.)

Junk food, with its combination of salty, sweet, fatty and savory flavors, tends to taste incredibly good.

But the issue is, junk food normally has a lot of calories.

It is extremely easy to overeat. (Think of a potato crisp or chocolate squares, it is very hard to just have a couple of pieces or bits.)

The attraction of delicious, calorie-dense junk food can overpower the best of intentions. When diets fail to address this temptation, people are more likely to give in.

The problem lies in the calorie density of these tempting treats.

High in calories, low in nutrition, and often served in large portions, junk food packs a calorie punch that can quickly derail any diet plan.

Despite our best intentions, the pleasure derived from consuming these calorie-rich foods often overrides our self-control.

To succeed in a diet, it’s crucial to acknowledge this challenge and find strategies to manage cravings for junk food.


  1. There Are More Fast Food Places Than Ever Before

The convenience of fast food and takeout options can make it easy to revert to unhealthy eating habits when faced with a busy lifestyle.

In today’s fast-paced world, convenience is king, and the abundance of fast-food chains and quick meal delivery services makes unhealthy options readily available.

Fast food chains, vending machines, and convenience stores are practically everywhere, making high-calorie snacks and meals accessible at almost any time.

Combine an upsize burger meal deal with fries and soda and the calories can stack up. Now combine the convenience that you can get this food at nearly every major intersection, any hour, any day of the week. This makes the calories really add up for the week and the diet gets sabotaged.

The constant exposure to enticing, high-calorie, and often nutritionally poor food choices can de-rail even the most well-intentioned diet plans.

Weight Loss Tip To overcome this challenge, it’s vital to plan meals, seek out healthier takeout options. Develop strategies to resist the convenience trap by making informed food choices that align with long-term health goals.


  1. The Diet Doesn’t Educate the Person on Healthy Habits

Chicken Stir-Fry with Mixed Vegetables

Diets that focus solely on short-term weight loss goals without teaching sustainable, healthy habits set individuals up for failure in the long run.

You might be interested in this article – 100 Calorie Snack Ideas


  1. The Diet Doesn’t Encourage Exercise as Part of the Long-Term Solution

A holistic approach to weight loss includes not only nutritional changes but also regular physical activity.

Diets that neglect exercise as part of the plan often fall short of achieving lasting results.

Walking, treadmill, running, weight training, Pilates, yoga, sports are just some options you can work in to your plan.

Are exercise bikes good for fat loss

An exercise bike is another great way to burn some calories and is low impact. For more details, click on – Are Exercise Bikes Good For Fat Loss?


  1. Not Planning Your Meals

Lack of meal planning can lead to impulsive food choices and overeating, interrupting your dieting efforts.

The saying of “if you fail to plan, you plan to fail” can be very true in weight loss.

For ideas and tips, visit – Meal Prep And Planning


  1. Bad Diets, Fad Diets And Scams

Another reason your diet might fail is, some diets are just plain awful, dangerous or are designed to steal your money.

A lot of bad diet plans will try and over-complicate things.

They talk about things that really only make a small difference in weight loss.

Bad or fad diets may mention as a cure or cause like: detox, hormones, fatty liver, blood sugar, body type, carbs are evil, blood sugar, celebrity, moon cycle, apple cider vinegar, keto gummies, TikTok diet, bulletproof coffee, caveman, rare herb, etc. Okay we are getting carried away, but you get the point. While some of these can be important, most make little to no difference to individuals for overall weight loss.

Understand that you have to be in a calorie deficit to lose fat. All the other talk and marketing hype is normally to try and make you believe your weight gain is due to something else beyond your control and the basics of weight loss don’t work.

When folks realize the diets are not working (because the diet is concentrating on the wrong thing) they understandably quit.


  1. Excessive Use Of Fat Loss Supplements

Fat loss supplements

Diets often fail when relying solely on fat loss supplements because depending on them can create a false sense of security, encouraging poor food choices.

Forget the sales advertisements, most fat loss supplements don’t work, or they make very little difference overall.

A lot of bad quality supplements use ingredients with no scientific evidence.

For ingredients that might be marginally helpful for fat loss, they are normally under-dosed anyway and are overly expensive supplements.

Educate yourself into what really works and makes a difference.

Sustainable weight management and overall health depend on good nutrition habits, not quick-fix supplements.


  1. Unrealistic Expectations

I lost 60 pounds in three days! We are exaggerating of course, but you get the picture of some phony marketing hype.

Fake results, social media influencers, and celebrities can give people false expectations, and unrealistic goals.

Some real results of actual people can also be discouraging. Don’t compare to other people who might be genetically gifted and have an athletic builds with very low body fat.

Also some of the pictures are photoshopped, or the model has dieted for 12 weeks for that one photoshoot. Good lighting and camera angles can have a dramatic effect.

Expecting rapid, dramatic results can lead to disappointment and frustration when they don’t materialize.


  1. Lack of Social Support

Trying to adhere to a diet can be challenging without a supportive network for some people.

Weight loss groups, Reddit forums and companies like Weight Watchers can help individuals with group support.

Walking groups and gym buddies can also be helpful for motivational.


  1. Not Tailored to Individual Preferences

Diets that don’t consider personal food preferences and cultural factors may not be sustainable in the long term.


  1. Lack of Accountability

Without being accountable, it’s easy to blame if the diet plan is not working and quit.

This might sound harsh, but blaming your genetics, diet plan or whatever (…enter your excuse here…) while eating excessively and watching Netflix all day won’t help.

Be aware of your activity levels and what you eat. Take responsibility if you are putting on weight.


  1. Weighing Yourself Everyday

Weight scales

Some people will give up on the diet when the scales aren’t moving down. This can be very discouraging, but remember your weight will fluctuate from day to day.

Just weigh yourself two, three or four times a week, not every day.

If you are weight training, you might have put on muscle and start looking toned, but if you just rely on the scales, you can get discouraged easy.

Better yet, use a combination of weight scales, dress or belt size, tape measure and the mirror to gauge how the diet is working.

A weight loss plateau can also happen.


The Best Diets

Now we have covered reason why fat loss diets fail, let’s look at some points that good weight loss diets have in common.

The best diets may include a couple or a majority of these factors:

  • Focus on being in a calorie deficit: Negative energy balance.
  • Increase protein intake: Protein helps maintain muscle loss when dieting and helps folks stay fuller.
  • They include a wide range of foods: Vegetables, fruits, lean meats, healthy fats, wholegrains, fish, dairy, etc. They don’t eliminate certain foods or macronutrients.
  • Weight training: Weights help maintain muscle mass when dieting and can help get you your best body ever when combined with sensible training.
  • Encourage learning about nutrition: You don’t have to be a dietician to know how to lose weight, but a little bit of education goes along way. You can then know what will work and what to avoid.
  • Promote healthy long term habits:
  • Plan: This helps when life gets hectic.
  • Moderation, not extreme: These diets are easier to follow and work in with your life.


19 Reasons Why Diets Fail Infographic


Diets Don’t Work? Is There Truth To This?

Ben Carpenter has some great practical, YouTube videos. Here is one below about – “Diets Don’t Work”? Is There Truth To This?



Understanding why diets fail can help you navigate your weight loss journey more effectively.

Keep in mind the fundamental principle of energy balance, and look for diets that align with this concept while avoiding the common pitfalls discussed above.

By selecting a sustainable, balanced approach to weight loss, you can increase your chances of achieving and maintaining your desired results.

Remember, successful diets promote not only short-term changes but also long-term healthy habits.


Resources, References And Information

Why Doesn’t Energy Balance Work In Weight Loss?