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The Truth About Extreme Diets: Short-Term Gains, Long-Term Pains

Updated: Mar 31

From the trendy ketogenic diet to the meat-heavy carnivore diet and the plant-based vegan diet, these approaches often promise quick weight loss but raise questions about sustainability and long-term health. Let's explore why these diets may work in the short term but might not be the best solution for lasting health and wellness.


Understanding Extreme Diets:

Ketogenic Diet (Keto):

The primary goal of the Ketogenic diet is to induce a metabolic state called ketosis. Normally, your body relies on carbohydrates as its primary source of energy. However, when carbohydrate intake is drastically reduced, such as in the keto diet, the body begins to burn fat for fuel instead. Going into Ketosis, depends on how well an individual follows the macros of a keto diet. Research suggests that adherence to the ketogenic diet varies widely among individuals, with some studies reporting dropout rates ranging from 10% to 45% due to challenges such as restrictive food choices, difficulty maintaining ketosis, and side effects such as the "keto flu."

The rapid initial weight loss experienced by many individuals starting a ketogenic diet can largely be attributed to two primary factors: water loss and reduced glycogen stores. Carbohydrates are stored in the body in the form of glycogen. For every gram of glycogen, 3-4 grams of water are also retained. When carbohydrates are drastically reduced, as in the case with a keto diet, glycogen stores become depleted. When the body begins to release the water bound to glycogen, the results are loss of rapid water weight. It’s important to distinguish between water weight loss and fat loss when assessing progress on a ketogenic diet. Sustainable, long-term fat loss typically occurs at a slower rate than the initial water loss. While rapid initial weight-loss can provide motivation, it is essential to focus on overall health and sustainable habits associated with nutrient density, rather than solely relying on a scale as a measurement of success.

Source: Phinney, S.D., Horton, E.S., Sims, E.A., Hanson, J.S., Danforth Jr, E., & LaGrange, B.M. (1980). Capacity for moderate exercise in obese subjects after adaptation to a hypocaloric, ketogenic diet. Journal of Clinical Investigation, 66(5), 1152–1161.

Source: Paoli, A., Rubini, A., Volek, J.S., & Grimaldi, K.A. (2013). Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. European Journal of Clinical Nutrition, 67(8), 789–796.

Source: Hallberg, S.J., McKenzie, A.L., Williams, P.T., Bhanpuri, N.H., Peters, A.L., Campbell, W.W., Hazbun, T.L., Volk, B.M., McCarter, J.P., Phinney, S.D., & Volek, J.S. (2018). "Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-Randomized, Controlled Study." Diabetes Therapy, 9(2), 583–612.


Carnivore Diet:

The carnivore diet is an extreme dietary approach that emphasizes the consumption of animal products while excluding all plant-based foods. This includes meat, poultry, fish, eggs, and certain dairy products, while excluding fruits, vegetables, grains, legumes, and other plant-derived foods.

Proponents of the carnivore diet claim that eliminating plant foods can lead to various health benefits, including improved digestion and relief from autoimmune conditions. They argue that certain plant compounds, such as lectins, phytates, and oxalates, may be harmful to human health and that removing them from the diet can reduce inflammation and alleviate symptoms of autoimmune diseases.

Critics of the carnivore diet raise concerns about the potential for nutrient deficiencies due to the exclusion of plant foods, which are rich sources of essential vitamins, minerals, fiber, and phytonutrients. Additionally, there is a lack of long-term research on the safety and efficacy of the carnivore diet, making it difficult to assess its potential risks and benefits accurately.

Source: Lennerz, B.S., Alsop, D.C., & Ludwig, D.S. (2019). "The Carnivore Diet: Is Eating Only Meat Healthy?" The Journal of Clinical Endocrinology & Metabolism, 104(12), 6201-6203.


Vegan Diet:

The vegan diet is a plant-based eating pattern that excludes all animal products, including meat, poultry, fish, dairy, eggs, and honey. Instead, it emphasizes the consumption of plant-based foods such as fruits, vegetables, grains, legumes, nuts, and seeds.

The vegan diet has been associated with various potential health benefits, including a lower risk of chronic diseases such as heart disease, hypertension, type 2 diabetes, certain cancers, and obesity. Additionally, adopting a vegan diet is often cited as a way to reduce environmental impact, as animal agriculture is a significant contributor to greenhouse gas emissions, deforestation, and water pollution.

While a well-planned vegan diet can provide all the essential nutrients, there are concerns about potential deficiencies in certain nutrients that are primarily found in animal products. These include vitamin B12, iron, and omega-3 fatty acids. Vegans are advised to ensure adequate intake of these nutrients through fortified foods, supplements, and inclusion of plant-based sources rich in these nutrients, such as fortified cereals, fortified plant milks, legumes, nuts, seeds, and algae-based supplements.

Source: Melina, V., Craig, W., & Levin, S. (2016). "Position of the Academy of Nutrition and Dietetics: Vegetarian Diets." Journal of the Academy of Nutrition and Dietetics, 116(12), 1970-1980.

Source: Dinu, M., Abbate, R., Gensini, G.F., Casini, A., & Sofi, F. (2017). "Vegetarian, Vegan Diets and Multiple Health Outcomes: A Systematic Review with Meta-Analysis of Observational Studies." Critical Reviews in Food Science and Nutrition, 57(17), 3640-3649.

Source: Pawlak, R., Lester, S.E., & Babatunde, T. (2014). "The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature." European Journal of Clinical Nutrition, 68(5), 541-548.


Short-Term Success vs. Long-Term Sustainability:

Extreme diets, such as very low-calorie diets or those that severely restrict certain food groups like carbohydrates or fats, often result in rapid initial weight loss due to several factors:

Calorie Restriction: Most extreme diets involve significant calorie restriction, leading to an immediate reduction in energy intake. When the body consumes fewer calories than it expends, it turns to stored energy sources, primarily fat stores, to meet its energy needs. This deficit leads to weight loss over time.

Decreased Sodium Intake: Some extreme diets may inadvertently lead to a reduction in sodium intake, either due to food restrictions or changes in eating habits. Sodium plays a crucial role in regulating fluid balance in the body. A decrease in sodium intake can result in less water retention, further contributing to rapid weight loss.

In essence, Ketogenic, carnivore, and vegan diets likely share a commonality: a focus on consuming less processed foods, which often translates to reduced calorie and sodium intake. It's crucial to recognize that the most scientifically supported method for weight loss is through a calorie deficit, also referred to as an energy deficit. When the body lacks sufficient readily available resources for daily activities, it resorts to tapping into its stores, promoting fat loss. However, it's important to acknowledge that there may be more sustainable approaches to achieving a calorie deficit tailored to individual needs. Not everyone possesses the time, energy, and resources required to safely maintain an extreme diet.

Source: "Nutrition and healthy eating." Mayo Clinic, "The role of energy expenditure in the differential weight loss in obese women on low-fat and low-carbohydrate diets." The American Journal of Clinical Nutrition.


Quick Fix Mentality:

Extreme diets appeal to individuals looking for quick fixes or rapid results, particularly for special occasions or events. The promise of significant weight loss in a short period can be enticing for those seeking immediate gratification.

While success stories and anecdotal evidence may highlight the effectiveness of extreme diets in the short term, it's essential to approach these diets with caution. Rapid weight loss often comes with potential risks and drawbacks, including nutrient deficiencies, metabolic adaptations, and difficulty maintaining weight loss over time. Long-term success and overall health should be prioritized over short-term results when considering dietary approaches for weight loss. Consulting with a healthcare professional or registered dietitian can help individuals make informed decisions and develop sustainable strategies for achieving their health and wellness goals.

Source: Sumithran, P., Prendergast, L.A., Delbridge, E., Purcell, K., Shulkes, A., Kriketos, A., & Proietto, J. (2011). "Long-term persistence of hormonal adaptations to weight loss." New England Journal of Medicine, 365(17), 1597-1604.

Source: Johnston, C.S., Tjonn, S.L., & Swan, P.D. (2004). "High-protein, low-fat diets are effective for weight loss and favorably alter biomarkers in healthy adults." The Journal of Nutrition, 134(3), 586-591.


Energy Levels and Physical Fitness:

Holistic wellness extends to energy levels and physical fitness. While weight loss may be a goal for many, it's essential to prioritize energy balance and physical activity to support overall health. Regular exercise not only aids in weight management but also promotes cardiovascular health, muscular strength, flexibility, and mood regulation. A balanced diet that provides adequate nutrients and energy supports optimal physical performance and enhances overall well-being.

Source: Jacka, F.N., O’Neil, A., Opie, R., Itsiopoulos, C., Cotton, S., Mohebbi, M., Castle, D., Dash, S., Mihalopoulos, C., Chatterton, M.L., Brazionis, L., Dean, O.M., Hodge, A.M., & Berk, M. (2017). "A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial)." BMC Medicine, 15(1), 23.



A More Individualized Approach to Health:

By listening to their bodies and seeking personalized guidance when navigating dietary choices, individuals can identify sustainable lifestyle habits that promote optimal health and longevity. Whether it's adopting a balanced Mediterranean-style diet, incorporating more plant-based foods, or making gradual changes to improve dietary quality, finding an approach that works best for each individual ensures greater adherence and success in the long run.

While extreme diets like keto, carnivore, and veganism may offer short-term weight loss results, they often come with potential risks and challenges that make them unsustainable as long-term solutions. Instead, prioritize a balanced approach to nutrition and lifestyle that supports overall health and well-being for the long haul. Remember, there's no one-size-fits-all solution, so listen to your body and seek personalized guidance when navigating dietary choices.

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