Image of person eating breakfast foods to represent fad diets

Why you should be cautious about fad diets

Written on April 14, 2023 by Sendra Yang, PharmD, MBA. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Obesity is now considered a global epidemic because of its continuous increase in prevalence in developed countries.[1] Almost half of the US adult population in the United States is obese or overweight.[2] Being obese or overweight puts a person at higher risk of developing cardiovascular disease, hypertension, type 2 diabetes, and liver and kidney diseases.[3] Due to the increasing awareness of weight-related health diseases, people are searching the internet for information on how to lose weight. According to a recent study, the number of internet search queries for losing weight increased from 2004 to 2018.[4] Fad diets are often presented as a quick solution for weight loss. They often make bold claims that can appeal to people struggling to lose weight. While trying the latest diet trend may be tempting, it’s wise to approach these diets cautiously.

What are fad diets?

A fad diet is broadly described as a dieting process that focuses on eating specific types of food, eating specified portions, or restricting certain foods. Fad diets can be differentiated from a healthy and balanced diet by their tendency to [5]:

  • Promote rapid weight loss
  • Omit entire food groups
  • Be nutritionally inadequate
  • Emphasize short-term weight loss changes
  • Have health consequences for individuals with underlying chronic health issues
  • Reduce the importance of physical activity
  • Lack of scientific evidence or support

Some popular fad diets are the South Beach diet, the Paleo diet, and the Atkins diet. Although some popular fad diets have garnered positive anecdotal evidence, research studies have questioned their practical long-term health benefits. [6,7] Some examples of viral fad diets are the banana diet, the cabbage soup diet, the grapefruit diet, or the raw food diet. Many of these fad diets have come and gone.

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The problem with fad diets

While fad diets may promise fast weight loss, they often come with risks and adverse side effects. Some reasons why you should be cautious about fad diets:

Nutrient deficiencies

Many fad diets eliminate entire food groups, which can lead to nutrient deficiencies.[5] For example, the keto diet eliminates most carbohydrates and promotes avoiding dairy products and grains. A keto diet can put you at risk for calcium, fiber, and vitamin D deficiencies; these nutrients are critical to bone health and prevent constipation. Another example is the Atkins diet, which restricts carbohydrates and emphasizes protein and fat intake. Carbohydrates provide the body with its primary source of energy, glucose. When your food choices are limited to certain food groups, you may lose micronutrients such as vitamins C and A, calcium, zinc, fiber, or folic acid.[8]

Alters metabolic system

Some fad diets can alter a healthy metabolism, making it harder to lose weight in the long term.[5] Some fad diets emphasize complete carbohydrate restriction or eating only certain foods. For example, very low-calorie diets can slow your metabolism, potentially making it harder to burn calories and lose weight.[9] The keto diet induces your body to enter a state of ketosis. Ketosis is a metabolic state wherein your body uses to burn fat for energy instead of glucose. Adhering to a strict keto diet has been shown to lower blood sugar levels. The keto diet can benefit some people without underlying health effects like diabetes.[10] For people with diabetes, low blood sugar is a health risk for hypoglycemia.

Weight regains

Many people who lose weight on a fad diet regain it once they return to regular eating habits.[5,11] Weight regains can lead to a cycle of yo-yo dieting, harming your health. People may transition to relaxing dieting discipline and resuming their former routines. These weight fluctuations are linked to a higher risk of increasing weight with each weight regain.[11]

Adverse health side effects

Some fad diets can cause harmful side effects, such as constipation, headaches, and fatigue.[5] In extreme cases, they can even lead to more severe health problems. Health experts worry about how a long-term keto-style diet can affect diabetes management. You may overconsume saturated fat and protein far above recommended levels because you eat so much meat. This can increase your risk of developing cardiovascular disease. [12]

What does the CDC say about fad diets?

According to the Centers for Disease Control and Prevention (CDC), though fad diets promise fast results, they have many drawbacks and tend to fail in the long term. [13] A consistent and well-planned weight loss program is the most effective means to target a healthy weight goal. [13,14] The CDC recommends making small, attainable goals, sustaining these changes in your diet and lifestyle, and identifying reputable sources of information such as your healthcare professional or registered dietitian to help.

To better manage and reach your target weight goals, you should incorporate these five routines into your weight loss plan[13-17]:

  • Eating a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats
  • Limiting your intake of processed foods, sugary drinks, and saturated fats
  • Getting regular exercise
  • Getting enough sleep
  • Managing stress

Concluding thoughts on fad diets

While fad diets may promise quick weight loss, they have risks and adverse side effects you should be aware of. Instead of relying on fad diets, focus on making sustainable lifestyle changes that include a healthy diet and seeking professional help when weight management becomes challenging. You can achieve your weight loss goals by eating various healthy foods, getting regular exercise, and managing stress.

If you have questions or concerns about your weight, contact a healthcare provider to discuss your options. At Everlywell, you can schedule a consult from the comfort of your home with a certified clinician through the weight loss online option. You can partner with a clinician to discuss your weight goals and get lifestyle support and recommendations for your overall health.

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  1. Obesity and overweight. World Health Organization. URL. Published June 9, 2021.
  2. Adult obesity facts.Centers for Disease Control and Prevention. URL. Published February 11, 2021.
  3. Health effects of overweight and obesity. Centers for Disease Control and Prevention. URL. Published September 24, 2022. Accessed April 17, 2023.
  4. Teng Y, Huang SW, Li Z, et al. Seasonal variation and trends in the internet searches for losing weight: An infodemiological study. Obes Res Clin Pract. 2020;14(3):225-233. doi:10.1016/j.orcp.2020.04.001. URL.
  5. Tahreem A, Rakha A, Rabail R, et al. Fad diets: facts and fiction. Front Nutr. 2022;9:960922. doi:10.3389/fnut.2022.960922. URL.
  6. Manheimer EW, van Zuuren EJ, Fedorowicz Z, Pijl H. Paleolithic nutrition for metabolic syndrome: systematic review and meta-analysis. Am J Clin Nutr. 2015;102(4):922-932. doi:10.3945/ajcn.115.113613. URL.
  7. Westman EC, Mavropoulos J, Yancy WS, Volek JS. A review of low-carbohydrate ketogenic diets. Curr Atheroscler Rep. 2003;5(6):476-483. doi:10.1007/s11883-003-0038-6. URL.
  8. Fruit and vegetables. Department of Health, State Government of Victoria. URL. Published April 29, 2008. Accessed April 17, 2023.
  9. Weight loss: Feel full on fewer calories. Mayo Clinic. URL. Published March 22, 2022. Accessed April 17, 2023.
  10. The pros and cons of keto to manage diabetes. Cleveland Clinic. URL. Published August 23, 2022. Accessed April 17, 2023.
  11. Maclean PS, Bergouignan A, Cornier MA, Jackman MR. Biology’s response to dieting: the impetus for weight regain. Am J Physiol Regul Integr Comp Physiol. 2011;301(3):R581-R600. doi:10.1152/ajpregu.00755.2010. URL.
  12. Paleo diet: What it is and why it’s not for everyone. UC Davis Health. URL. Published February 6, 2022. Accessed April 17, 2023.
  13. Healthy weight, nutrition, and physical activity. Centers for Disease Control and Prevention. URL. Published June 3, 2022. Accessed April 17, 2023.
  14. Losing weight: Getting started. Centers for Disease Control and Prevention. URL. Published June 3, 2022. Accessed April 17, 2023.
  15. Healthy eating for a healthy weight. Centers for Disease Control and Prevention. URL. Published March 8, 2023.Accessed April 17, 2023.
  16. Cutting calories. Centers for Disease Control and Prevention. URL. Published June 3, 2022. Accessed April 17, 2023.
  17. Physical activity for a healthy weight. Centers for Disease Control and Prevention. URL. Published June 16, 2022. Accessed April 17, 2023.
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