Are you on a Fad Diet?

Meyken Houppermans, PhD. CrossFit Level 3 Trainer.
Founder and Head Coach
Are you on a clean and healthy diet? Are some foods are bad for you? Do you take supplements? You might be on a Fad Diet! A Fad Dietis promises quick weight loss sand health. Evidence is lacking, and the diet can have negative health consequences We discuss: Keto, Paleo, Mediterranean,Vegetarian, Intermittent Fasting and Detox, and the effect on athletic performance.

What is a Fad diet

A Fad Dietis a popular diet, often used as a quick fix for weight loss. These diets seem appealing due to proposed claims, but they lack scientific evidence regarding their effectiveness. Research shows negative health consequences of long-term adherence to these diets. 

How to recognize a Fad Diet:

-       Promises rapid weight loss

-       Absence of physical activity guidelines

-       Promotes short-term changes rather than achieving life long sustainable goals

-       Focuses on one type of food or eliminates any food group

-       Cannot be maintained for life long period

-       Nutritional adequacy is questionable

-       Fails to provide health warnings for those with chronic diseases

-       Lacks scientific evidence to support the claims

Popular Fad diets are Keto, Paleo, Mediterranean, Vegetarian/ vegan, Intermittent Fasting, and Detox diet. In previous articles we discussed Paleo and Detox. 

Ketogenic Diet

Ketogenic diet was developed for the treatment of epilepsy. It prescribes a diet of 20% protein, 65-80% fat and 5-10% carbs. The diet includes fasting, hydration, physical activity, and intake of electrolytes and nutritional supplements. 

How does it work?

Ketogenic diet works by bringing certain metabolic changes to the body. Glucose is the body’s primary energy source. Low carb intake resulting in a metabolic shift toward gluconeogenesis and ketogenesis.The preliminary shortage is managed by the production of glucose from glycerol, glutamine, alanine, and lactic acid (gluconeogenesis). To keep up with the needs of the body, ketone bodies come into play and serve as an alternate energy source for the body (ketogenesis). At this stage due to low blood glucose feedback, secretion of insulin is also low, which further reduces the stimulus for fat and glucose storage. This ketotic state remains active until the body’s carbohydrates needs are fulfilled.u 

How effective is it?

Research shows ketogenic diet is effective for epileptic patients and has neuro protective action in various neurological illnesses like Alzheimer’s disease, Parkinson’s disease, traumatic brain injury, depression, autism, and narcolepsy.

Research results on the effectiveness for weight loss are inconclusive. The mechanism behind successful weight loss is still a scientific debate, possibly the appetite suppressing effect of ketone bodies plays a role. 

Health risks?

Short-term effects of the ketogenic diet are vomiting, nausea, gastrointestinal discomfort, fatigue, dizziness, feeling faint, decreased energy, heart beat alterations, hypoglycemia and lethargy.  

Longer- term effect are increase cholesterol levels, and therefor increased risk of cardiovascular disease. Low bone mineral density, kidney stones and fracture are also mentioned in relation to this diet. Also, hypercalcemia (increasing the risk of affecting bones and the functioning of heart and brain); low parathyroid hormone levels (increasing the risk of health issues such as muscle cramps and abdominal heart rhythm); impaired renal function; and low alkaline phosphate levels which is accompanies by symptoms such as nose bleeds and shortness of breath during activities.  

Athletic performance

Ketogenic diets are restrictive of carbohydrates and proteins. The diet can be difficult to adhere to. It can negatively affect performance in high intensity sport, and a lower protein intake is not beneficial for athletic performance. It also seems Ketodiet can lead to the loss of muscle mass in resistance-trained individuals such as CrossFitters.[1] 

Mediterranean Diet

The Mediterranean diet prescribes whole grains, legumes, fruits, vegetables, olive oil, fish, and nuts with a moderate allowance of alcohol, dairy products, and meat. Traditionally, this diet derives its most calories from fish and plant-based foods, with 30% of total calories from unsaturated fat, 50% carbs and 20% protein. 

How effective is it?

Mediterranean diet is the most extensively studied diet to date. Research shows this diet is nutritionally adequate for the general public and may have the potential of preventing micronutrient deficiencies. It has preventive and therapeutic potential for many chronic diseases like non-alcoholic fatty live disease (TOFI, thin on the outside, fat on the inside), cardio vascular disease, metabolic syndrome, colorectal and breast cancer, decreased risk of type 2 diabetes. 

Health risks?

There is no evidence of adverse effects associated with the Mediterranean diet The diet has preventive and therapeutic potential for many chronic diseases; is highly suitable for the general public for the prevention of micronutrient deficiencies and specifically for patients who are more health-conscious than just weight loss oriented. 

Athletic performance

The Mediterranean dietis a low inflammatory diet linked to improved power and muscle endurance and body composition.[2]  

Vegetarian/ vegan Diet

The vegetarian diet prescribed no consumption of meat and meat products, seafood, poultry. The vegan diet prescribes no consumption of animal products like eggs, animal milk, and honey.   

How effective is it?

Research shows a link between (red) meat and increased risk of chronic diseases, while others indicate a positive association between low meat intake and life expectancy (How bad is eating meat?)

Research shows vegetarians and vegans have a lower risk of cardiometabolic disease, high cholesterol and cancer, partially due to the high intake of fiber (Weight loss and fiber and Your poop tells it all) and abstinence of red meat and low intake of saturated fat and cholesterol. Some studies show vegetarians also have increased life expectancy.

Generally, vegetarians are more health-conscious and have lower BMI than meat- and fish eaters and compared to the general population. Furthermore, research shows, the higher the intake of vegetable-fruit -soy dietary pattern (Animal or plant protein, which is better for athletes?), the lower the breast cancer hazard ratio among post menopausal women (Tackle menopause with food).  

Health risks?

The vegetarian/ vegan diet is associated with fluctuations in micronutrients intake because of the day-to-day variation in the menu. Potential risks are micronutrient deficiencies such as calcium, zinc, iron, vitamin E, vitamin B12, essential fatty acids, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). (Do you need supplements?) and Calcium supplement or dairy?) Supplementation is advised. Vegetarian diet can be helpful inchronic disease prevention and treatment.  

Athletic performance

Vegan athletes are at risk of micronutrient deficiencies and decreased leucine content, and therefore, decreased muscle protein synthesis. Research does not show decreases in performance compared to meat- eaters.[3] 

Intermittent Fasting

Intermittent fasting centers around scheduled eating, with phases of not eating followed by phases of normal eating with the goal to lose weight.

How effective is it?

The evidence regarding the effectiveness on weight loss is inconclusive. Research shows in some cases body weight remains the same, in other cases body weight drops due to lower caloric intake. Results seem to be only short- term and comparable to that of a calorie- restricted diet.

Health risks?

Research shows intermittent fasting increases fluctuations in free fatty acids in the bloodstream. High levels of free fatty acids increase the risk of type 2 diabetes and cancer. Furthermore, intermittent fasting reduces insulin sensitivity, which increase the risk of type 2 diabetes and metabolic syndrome. The evidence regarding the effectiveness on weight loss is inconclusive.

Intermittent fasting might be an option for people who find it difficult to structure their eating pattern by eating on set times, rather than snacking throughout the day. It might not be suitable for people with comorbidities or specific needs.

Athletic performance

Research shows no benefit to athletic performance while fasting. Intermittent fasting can have crucial effects on physical and intellectual performance (memory deficits), by affecting various aspects of bodily physiology and biochemistry. Intermittent fasting can lead to decreases in sprint speed and worsening time to exhaustion.[4]

Create your own health!©


[1] Ashtary-LarkyD, Bagheri R, Bavi H, Baker JS, Moro T, Mancin L, Paoli A. Ketogenic diets,physical activity and body composition: a review. Br J Nutr. 2022 Jun28;127(12):1898-1920. doi: 10.1017/S0007114521002609. Epub 2021 Jul 12. PMID:34250885; PMCID: PMC9244428.; Kaufman M, Nguyen C,Shetty M, Oppezzo M, Barrack M, Fredericson M. Popular Dietary Trends' Impacton Athletic Performance: A Critical Analysis Review. Nutrients. 2023 Aug9;15(16):3511. doi: 10.3390/nu15163511. PMID: 37630702; PMCID: PMC10460072.;Tahreem A, Rakha A, Rabail R, Nazir A, Socol CT, Maerescu CM, Aadil RM. FadDiets: Facts and Fiction. Front Nutr. 2022 Jul 5;9:960922. doi:10.3389/fnut.2022.960922. PMID: 35866077; PMCID: PMC9294402.

[2] KaufmanM, Nguyen C, Shetty M, Oppezzo M, Barrack M, Fredericson M. Popular DietaryTrends' Impact on Athletic Performance: A Critical Analysis Review. Nutrients.2023 Aug 9;15(16):3511. doi: 10.3390/nu15163511. PMID: 37630702; PMCID:PMC10460072.; Tahreem A, Rakha A, Rabail R, Nazir A, Socol CT, MaerescuCM, Aadil RM. Fad Diets: Facts and Fiction. Front Nutr. 2022 Jul 5;9:960922.doi: 10.3389/fnut.2022.960922. PMID: 35866077; PMCID: PMC9294402.

[3] Idem

[4] Cherif A, Roelands B, MeeusenR, Chamari K. Effects of Intermittent Fasting, Caloric Restriction, and RamadanIntermittent Fasting on Cognitive Performance at Rest and During Exercise inAdults. Sports Med. 2016 Jan;46(1):35-47. doi: 10.1007/s40279-015-0408-6. PMID:26438184.; Levy E, Chu T. Intermittent Fasting and Its Effects on AthleticPerformance: A Review. Curr Sports Med Rep. 2019 Jul;18(7):266-269. doi:10.1249/JSR.0000000000000614. PMID: 31283627.; Kaufman M, Nguyen C, Shetty M,Oppezzo M, Barrack M, Fredericson M. Popular Dietary Trends' Impact on AthleticPerformance: A Critical Analysis Review. Nutrients. 2023 Aug 9;15(16):3511.doi: 10.3390/nu15163511. PMID: 37630702; PMCID: PMC10460072.; Tahreem A, Rakha A, Rabail R, Nazir A, Socol CT,Maerescu CM, Aadil RM. Fad Diets: Facts and Fiction. Front Nutr. 2022 Jul5;9:960922. doi: 10.3389/fnut.2022.960922. PMID: 35866077; PMCID:PMC9294402.