Learn everything about the keto diet, including its history, principles, benefits, and impact on fat loss and performance.
What is the Ketogenic Diet?
The ketogenic diet (keto diet) is a low-carb, high-fat diet that triggers a metabolic state called ketosis. This occurs when carbohydrate intake is significantly reduced, forcing the body to burn fat for energy. In ketosis, the liver produces ketone bodies, which serve as an alternative fuel source, particularly for the brain.
The keto diet allows individuals to function with little to no carbohydrate intake while maintaining energy levels. From an evolutionary and physiological perspective, ketosis is a survival mechanism that helps the body sustain energy during food shortages.
How Does the Keto Diet Work?
To enter and stay in ketosis, your diet should be:
✅ High in healthy fats (70-80% of daily intake)
✅ Moderate in protein (10-20% of daily intake)
✅ Very low in carbohydrates (5-10% of daily intake)
Since insulin plays a crucial role in fat storage, keto aims to lower insulin levels, potentially promoting fat loss.
History of the Keto Diet
Unlike most diets that originate from fitness trends, the ketogenic diet was first developed for medical purposes. It was used in the 1920s to manage epilepsy in children, as ketosis can stabilize brain metabolism. Over time, it gained popularity as a fat-loss tool and a method for improving metabolic health.
Keto Diet vs. Low-Carb Diet
Both diets reduce carbohydrate intake, but they function differently:
• Low-Carb Diet: Reduces carb intake but does not necessarily induce ketosis.
• Keto Diet: Keeps carbs low enough to maintain ketosis, shifting the body’s primary fuel source to fat.
If you’re going low-carb, going fully keto may be beneficial to help your body fully adapt.
Ketogenic Diet vs. Ketoacidosis
Many people confuse nutritional ketosis with diabetic ketoacidosis (a dangerous condition for diabetics). Here’s the difference:
🔹 Nutritional Ketosis: Normal and controlled, with ketone levels between 0.5 – 3.0 mmol/L.
🔹 Diabetic Ketoacidosis: A dangerous condition where ketones rise above 5.0 mmol/L due to insulin deficiency.
For healthy individuals, ketosis is completely safe and even beneficial.
How to Stay in Ketosis
To remain in ketosis, follow these key principles:
✔ Keep carbs below 5-10% of daily calories. Most people stay in ketosis by consuming 20-50g of carbs per day.
✔ Limit protein intake to avoid excess gluconeogenesis (where protein is converted into glucose).
✔ Check ketone levels using urine strips or blood tests to ensure you’re in ketosis.
Does Keto Require Meal Timing or Phases?
The keto diet does not require specific meal timings, but many followers combine it with intermittent fasting (IF) to enhance results.
Some people also follow a Cyclic Keto Diet (CKD), where they stay in ketosis for 5 days, followed by a 1-2 day carb refeed.
Who Should Follow the Keto Diet?
The ketogenic diet is ideal for:
✅ Individuals looking for sustained fat loss without strict calorie counting
✅ Those comfortable with limiting carbohydrate-rich foods
✅ People who want stable energy levels and reduced cravings
However, high-performance athletes or those doing intense strength training may struggle with reduced glycogen stores.
Is the Keto Diet Easy to Follow?
Some find keto easy due to reduced hunger and no calorie counting, while others struggle with food restrictions.
⚠ Challenges include:
The “keto flu”, where the body adapts to low carbs, causing fatigue and headaches
Social limitations, as many foods (e.g., bread, pasta, fruits) are restricted
Strict macronutrient tracking to maintain ketosis
Despite these challenges, many report long-term adherence and success with keto.
Scientific Studies on the Keto Diet
The ketogenic diet is one of the most researched diets, second only to the Mediterranean diet.
🔬 Fat Loss & Weight Management
A tightly controlled study found that while low-carb diets increase fat oxidation, they may not provide a “metabolic advantage” over other calorie-controlled diets.
Key study results:
📌 Low-carb vs. low-fat diets: Both led to fat loss, but reducing total calories was the primary driver.
📌 Calorie control remains crucial—fat loss occurs primarily due to a caloric deficit, not just low carb intake.
🔬 Performance & Athletic Ability
The keto diet has mixed results in sports performance:
✔ Benefits: Improved body composition, weight loss, and VO2 max in endurance athletes.
❌ Drawbacks: Reduced glycogen levels, which can negatively impact high-intensity activities.
Studies show that ketogenic diets may impair recovery and max effort performance, making them less ideal for strength athletes.
Conclusion: Should You Try the Keto Diet?
The ketogenic diet is a powerful tool for weight loss, metabolic health, and appetite control. However, it is not a magic solution.
🔹 Best for: Fat loss, metabolic health, and individuals who enjoy low-carb eating.
🔹 Not ideal for: High-intensity athletes or those who struggle with food restrictions.
If you’re considering keto, focus on whole foods, track your macros, and be patient with the adaptation process!
References
1. Hall, K. D., et al. (2016). Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction in people with obesity. Cell Metabolism, 23(5), 1040-1048.
👉 DOI: 10.1016/j.cmet.2016.04.010
2. Hall, K. D., et al. (2015). Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. American Journal of Clinical Nutrition, 102(4), 787-795.
👉 DOI: 10.3945/ajcn.115.112581
3. Zinn, C., et al. (2017). Ketogenic diet benefits endurance athletes by improving body composition and aerobic capacity. Journal of the International Society of Sports Nutrition, 14(1), 22.
👉 DOI: 10.1186/s12970-017-0180-0
4. Phinney, S. D., et al. (1983). The human metabolic response to chronic ketosis without caloric restriction: Physical and biochemical adaptation. Metabolism, 32(8), 757-768.
👉 DOI: 10.1016/0026-0495(83)90105-1
5. Burke, L. M., et al. (2017). Low-carbohydrate, high-fat diet impairs exercise economy and negates performance benefit from intensified training in elite race walkers. Journal of Physiology, 595(9), 2785-2807.
6. Volek, J. S., et al. (2004). Metabolic characteristics of keto-adapted ultra-endurance runners. Metabolism, 53(10), 1338-1345.
👉 DOI: 10.1016/j.metabol.2004.06.014
7. Paoli, A., et al. (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.
