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How Is A Fad Diet Different Than A Low-Calorie Diet?

Fad Diet and Low Calorie Diet
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Written by Andrew Le, MD.
Last updated April 20, 2024

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With so many diet options in the market, it's easy to feel confused about which to choose. You may have heard of two popular diets: fad diets and low-calorie diets.

Fad diets are stylish eating plans that promise quick and significant weight loss. They might eliminate certain food groups or require you to eat specific types of food. On the other hand, low-calorie diets focus on reducing your overall calorie intake by eating healthy foods that provide your body with the essential nutrients it needs.

Understanding the difference between these two types of diets is crucial to selecting a healthy and sustainable weight loss plan that fits your needs.

In this article, we will compare how a fad diet differs from a low-calorie diet and discuss factors to consider when selecting a diet.

🔑 Key Takeaways

  • Fad diets are stylish eating plans that promise quick and significant weight loss, while low-calorie diets focus on reducing your overall calorie intake by eating healthy foods that provide your body with essential nutrients.
  • Fad diets may result in initial weight loss, but they are often not sustainable in the long run and can lead to nutritional deficiencies, metabolic damage, and weight regain.
  • Low-calorie diets are generally considered a safer and more sustainable weight-loss option.
  • It is important to be well-informed about fad diets before trying them, as they can have negative health consequences in the long term.
  • When considering a diet plan, it is essential to consider factors such as your health status, lifestyle, and food preferences.
  • Consulting a healthcare professional or a registered dietitian can help you choose a diet plan that is safe, effective, and tailored to your individual needs.

What Is A Fad Diet?

Fad diets have become popular for their promise of quick weight loss results. These diets typically limit certain food groups or macronutrients, such as carbohydrates or fats, and may require significantly reduced calorie intake or specific foods or supplements. It is estimated that 50% of the 45 million Americans who diet annually use fad diets.

While fad diets may result in initial weight loss, they are often not sustainable in the long run and can lead to nutritional deficiencies, metabolic damage, and weight regain. According to a study, fad diets are often marketed with claims that lack scientific evidence. The study also found that these diets can have negative health consequences in the long term and are generally unsustainable.

Before trying fad diets, it's important to be well-informed about this diet. Here are some examples you may have come across:

1. The Atkins Diet

The Atkins Diet is a low-carbohydrate, high-fat diet that emphasizes protein and fat while restricting carbohydrates. In some studies, it has been associated with weight loss ranging from 0.1% to 2.9%.

Although some studies have reported successful short-term weight loss with the Atkins Diet, its long-term effectiveness and safety still need to be determined. Despite the diet's short-term benefits, some experts have raised concerns about its long-term sustainability.

There are several potential long-term health risks associated with the diet. One concern is that the high fat intake could lead to an increased risk of heart disease. Additionally, the diet may not provide enough fiber, which could result in digestive issues and an increased risk of colon cancer. Finally, the high protein intake could strain the kidneys over time.

2. The Paleo Diet

The Paleo Diet encourages eating like our hunter-gatherer ancestors, emphasizing whole foods like meats, fish, fruits, and vegetables while excluding grains, dairy, and processed foods.

According to the study, the Paleo diet is not well-balanced as it excludes certain foods such as whole grains, legumes, and dairy products. This can lead to deficiencies in essential micronutrients that may negatively affect health. Those who follow the Paleo diet may also have insufficient calcium intake.

The study was conducted to assess the nutritional adequacy of this diet, which revealed that besides promoting weight loss through low intake of carbs, fats, and total calories, the diet also provided about 50% less calcium than the recommended amount.

3. The Detox Diet

Detox diets involve consuming only fruit and vegetable juices for a specific period, usually claiming to detoxify the body. However, there is limited scientific evidence to support the detoxification claims of these diets.

A study has shown that the success rate of dieting, in general, is low, which implies that achieving sustainable weight loss through detox diets may be challenging.

Although detox programs may be harmless, there are safety concerns over detox programs that use extreme methods. Fasting for long periods, restricting calories heavily, and taking certain dietary supplements can lead to adverse health effects, such as nutrient deficiencies, weakness, mood changes, dehydration, and more.

4. The Keto Diet

The Keto diet (KD) involves significantly reducing your carbohydrate intake. You consume only about 5-10% of your daily calories from carbohydrates. This contrasts with a typical diet, where carbohydrates make up a larger portion of your daily calorie intake.

While the KD may provide short-term benefits, its long-term effects on health are still being researched. Some concerns include potential nutrient deficiencies due to restricted food choices and the diet's sustainability over time.

Short-term minor side effects of the KD are quite common. These include vomiting, nausea, gastrointestinal discomfort, fatigue, dizziness, faintness, decreased energy, and heartbeat alterations.

Studies have found that individuals on KD therapy may experience lower-than-normal bone mineral density, which may lead to fractures. Kidney stones are also a common side effect, with 8.8% of study subjects experiencing it during treatment.

🗒️ Related Articles

Discover the differences and similarities between the popular diets, Keto and Intermittent Fasting, and choose the one that suits you best. Additionally, learn how to plan your meals effectively for weight loss.

If you want to learn more about these topics, you can check out some of our articles:

What Is A Low-Calorie Diet?

A low-calorie diet is a weight loss plan that involves consuming a limited number of calories, typically from 1,000 to 1,500 calories daily. The idea behind this diet is to create a calorie deficit of 500 to 750 calories per day, which is considered optimal for healthy weight loss.

Adopting a low-calorie diet plan can be challenging since it requires careful planning and effort to understand and recognize hunger cues, especially if you're used to a higher calorie intake.

Additionally, it is crucial to ensure that the 1,200 to 1,500 calories consumed are sufficient to fuel the body and provide all the necessary nutrients. It's recommended to consult a registered dietitian or healthcare professional to ensure you get all the nutrients your body needs while following a low-calorie diet.

What Are The Foods You Can Eat On The Low-Calorie Diet?

If you plan to eat fewer calories, knowing which foods you can eat is important to ensure you're still getting all the necessary nutrients. The basic idea is simple: eat fewer calories than your body burns. To follow this diet, you just need to remember a few things, such as:

  • Avoiding high-calorie foods
  • Monitoring your portion sizes to prevent overeating
  • Steering clear of sugary drinks

Below are the foods you can eat on the low-calorie diet:

Milk and Dairy Products

  • Low-fat milk
  • Low-fat lactose-free milk
  • Low-fat plain yogurt (Greek or traditional)
  • Low-fat cottage cheese
  • Milk alternatives (soy, almond, coconut, cashew, and hemp milks)


  • All fresh vegetables
  • All frozen vegetables
  • Low-sodium canned vegetables (should be drained and rinsed)

Fruit and Juices

  • All fresh fruit
  • All frozen fruit
  • Juice with no sugar added

Breads and Grains

  • Whole-wheat products, including bread, pasta, crackers, and cereals
  • Brown rice
  • Oats
  • Quinoa
  • Barley
  • Plain air-popped popcorn

Meats and Meat Substitutes

  • Skinless, boneless chicken or turkey
  • Loin or round cuts of meat (beef, pork, and lamb)
  • Fish
  • Shellfish
  • Eggs and egg whites
  • Dried beans and peas
  • Low-sodium canned beans (should be drained and rinsed)
  • Tofu
  • Tempeh
  • Nuts (limit to 1 ounce per serving)
  • Nut butters (limit to 2 tablespoons per serving)
  • Seeds


  • Olive oil (limit to 1 tablespoon per serving)
  • Canola oil (limit to 1 tablespoon per serving)
  • Nut or seed oils (limit to 1 tablespoon per serving)
  • Avocados (limit to ½ avocado per serving)
  • Low-fat mayonnaise (limit to 2 tablespoons per serving)
  • Whipped butter (limit to 1 tablespoon per serving)


  • Water
  • Sparkling water
  • Tea
  • Coffee


Maintaining a balanced diet is crucial for good health, but it can be challenging to obtain all the necessary nutrients from food alone. Fortunately, fruit and vegetable supplements can help fill the gap. We have conducted thorough research and put together a list of the best fruit and veggie supplements available on Amazon. This way, you can easily find high-quality products that support your overall well-being.

How Is A Fad Diet Different Than A Low-Calorie Diet?

Fad diets and low-calorie diets are two distinct approaches to managing weight and nutrition, and they differ in several key ways:

1. Nature and Duration

Fad diets gain quick popularity but usually fade away just as quickly. They are typically intended for short-term use.

Conversely, low-calorie diets focus on long-term weight management. These diets involve a sustained reduction in daily calorie intake and are designed for gradual, sustainable weight loss over an extended period of time.

2. Calorie Emphasis

Fad diets may not necessarily revolve around calorie counting or reduction as a primary focus. They often employ unconventional methods, such as restricting specific food groups or promoting certain "miracle" foods.

While, low-calorie diets reduce calorie intake below the body's energy expenditure. The primary goal is to create a calorie deficit to promote weight loss.

3. Nutritional Balance

Fad diets often tend to miss out on nutritional balance and may exclude complete food groups or essential nutrients. Following such diets can lead to vital nutrient deficiencies and pose potential health risks.

However, low-calorie diets are usually designed to provide a balanced intake of essential nutrients. These diets aim to fulfill nutritional requirements while reducing overall calorie intake.

4. Weight Loss Approach

Fad diets often promise rapid and sometimes unrealistic weight loss results. They may rely on unconventional methods or specific ingredients to achieve this.

While, low-calorie diets emphasize gradual and sustainable weight loss through calorie reduction and portion control. They focus on steady progress over time.

5. Scientific Basis

Many fad diets lack scientific validation and are often based on anecdotal evidence or marketing tactics rather than proper research.

On the other hand, low-calorie diets are based on established principles of calorie balance and have been thoroughly studied in clinical settings. They are supported by scientific evidence that proves their effectiveness

6. Long-Term Sustainability

Fad diets are usually not sustainable in the long run and can result in yo-yo dieting as individuals find it difficult to maintain them.

On the other hand, low-calorie diets are intended to be sustainable and can be incorporated as part of a long-term lifestyle change for managing weight.

What Are The Factors To Consider When Selecting A Diet Plan?

Several important factors must be considered when selecting a diet plan to ensure it aligns with your health goals and lifestyle. Here are the key factors to remember:

1. Health Goals

Determine your specific health objectives: weight loss, muscle gain, improved energy levels, or managing a medical condition. Your goals will influence the type of diet plan you choose.

For instance, if your goal is weight loss, consider a calorie-restricted diet plan that focuses on reducing your overall caloric intake and increasing your physical activity.

2. Nutritional Adequacy

Ensure that your diet plan provides your body with the essential nutrients, including vitamins, minerals, protein, carbohydrates, and healthy fats. Avoid diets that overly restrict particular food groups. Some examples of nutrient-dense foods that you can include in your diet plan are leafy green vegetables, fruits, whole grains, lean proteins such as chicken, fish, and legumes, and healthy fats like nuts, seeds, and avocado.

It's also important to drink plenty of water and limit your intake of added sugars, saturated and trans fats, and sodium. Remember that a balanced and varied diet is key to achieving nutritional adequacy.

3. Sustainability

Choose a diet plan you can realistically maintain over the long term. Avoid extreme or overly restrictive diets that may be challenging to stick with. For example, instead of going on a crash diet that severely restricts your calorie intake, consider making small changes over time that you can realistically stick to.

This could mean reducing your portion sizes, increasing your intake of fruits and vegetables, or swapping out high-calorie snacks for healthier options. Alternatively, you could try a more sustainable approach to weight loss, such as a whole- or plant-based diet, which focuses on eating nutrient-dense foods that promote health and well-being.

Remember, the key to sustainable weight loss is maintaining lifestyle changes over the long term rather than relying on quick fixes or fad diets.

4. Social and Emotional Impact

Consider how the diet plan may affect your social life and emotional well-being. Some diets can be isolating or lead to feelings of deprivation, which may impact your mental health. For example, a restrictive diet that eliminates entire food groups may make it challenging to dine out with friends or attend social gatherings where food is the centerpiece.

This can lead to feelings of isolation and negatively impact your social life. Similarly, feeling deprived or constantly hungry on a particular diet can affect your emotional well-being and even lead to disordered eating patterns. It's important to consider any diet plan's social and emotional impact before embarking on it.

5. Medical Considerations

If you have underlying medical conditions or allergies, consult a healthcare professional or registered dietitian to ensure the diet plan is safe and suitable for your health needs. For instance, if you have diabetes, you may need to monitor your carbohydrate intake carefully, so it's crucial to consult a healthcare professional or registered dietitian before starting any diet.

Similarly, suppose you have a history of heart disease. In that case, you may need to limit your sodium intake, so it's essential to seek medical advice before embarking on any new diet plan. In short, if you have any underlying medical conditions or allergies, consulting a healthcare professional or registered dietitian must ensure the diet plan is safe and suitable for your health needs.

6. Long-Term Health

Think about the impact of the diet plan on your overall health and well-being. A good diet plan should contribute to your long-term health and not compromise it. For example, a diet plan that consists of various fruits, vegetables, and lean proteins can provide the essential nutrients your body needs to function properly and maintain good health in the long run.

On the other hand, a diet plan that is heavily focused on processed foods, high in saturated fats, and low in fiber can lead to a host of health problems over time, such as obesity, heart disease, and diabetes. Therefore, choosing a balanced and nutritious diet plan that supports your long-term health and well-being is important.

Final Thoughts

A fad diet is typically a short-term, restrictive eating plan focusing on specific foods or food groups. In contrast, a low-calorie diet is a long-term approach that aims to reduce overall calorie intake for sustained weight management.

Setting realistic expectations and prioritizing long-term health is essential when considering a diet plan. Sustainable, gradual changes are generally healthier and more effective over time.

So, before embarking on any weight management journey, carefully evaluate the diet plan's nature, duration, nutritional balance, and scientific basis to ensure it aligns with your long-term well-being goals. Remember, your health is the ultimate treasure; a well-informed choice can lead to lasting benefits.

FAQs On Fad Diet And Low-Calorie Diet

What is the reason behind the initial success of most fad diets?

Fad diets work initially because they often cut calories or entire food groups, leading people to consume fewer calories or limited portions of certain foods.

How does fad diets contribute to weight gain?

When you follow a fad diet, your metabolism slows down, causing it to take longer to burn food into energy than before. Consequently, you are more likely to gain weight faster than you previously did. Furthermore, damaging your metabolism in this way can have dangerous consequences.

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Dr. Le obtained his MD from Harvard Medical School and his BA from Harvard College. Before Buoy, his research focused on glioblastoma, a deadly form of brain cancer. Outside of work, Dr. Le enjoys cooking and struggling to run up-and-down the floor in an adult basketball league.

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