What is a ketogenic diet?

Low-Carbohydrate and Very Low-Carbohydrate Diets

A Scientific Review of Benefits, Risks, and Hormonal Effects

Introduction

Low-carbohydrate (Low Carb) and very low-carbohydrate (VLCKD or Ketogenic) diets have gained widespread popularity in recent years as nutritional strategies for weight loss, blood sugar control, and managing metabolic disorders. While these diets offer significant benefits, they also have profound effects on the body’s endocrine (hormonal) and exocrine systems. Understanding these effects can help patients make more informed decisions and allow clinicians to guide them effectively.

Definition of Low-Carb and Ketogenic Diets

1. Low-Carbohydrate Diet (Low Carb)

• Typically includes less than 100–150 grams of carbohydrates per day.
• Focuses on reducing refined carbs and increasing healthy fats and proteins.

2. Very Low-Carbohydrate / Ketogenic Diet (VLCKD)

• Limits daily carbohydrate intake to less than 50 grams, often 20–30 grams.
• The body enters a state of ketosis, where it shifts from using glucose to ketone bodies for energy.

Scientific Benefits of Low-Carb Diets

1. Rapid Weight Loss

• Lower insulin levels promote lipolysis (fat breakdown) and reduced water retention.

2. Improved Insulin Sensitivity

• Reduced carb intake lowers blood sugar fluctuations and insulin demand.

3. Type 2 Diabetes Management

• Significant reductions in HbA1c and, in some cases, reduced need for medications.

4. Improved Lipid Profile

• Especially on ketogenic diets, triglycerides drop and HDL cholesterol increases.

Hormonal Effects of Low-Carb and Ketogenic Diets

Endocrine Hormones

1. Insulin
   • Drastically reduced secretion.
   • Improves insulin resistance in metabolic syndrome and diabetic patients.
2. Glucagon
   • Elevated levels in the absence of glucose; promotes ketogenesis and gluconeogenesis.
3. Leptin and Ghrelin (Appetite Hormones)
   • Leptin may decrease (due to body fat loss), but satiety often improves.
   • Ghrelin may rise in early stages, but high protein intake helps manage hunger.
4. Cortisol
   • May increase initially, especially with low caloric intake.
   • Some individuals experience metabolic stress, leading to sleep disturbances or fatigue.
5. Thyroid Hormones (T3, T4)
   • T3 may decline in some individuals without clinical hypothyroidism.
   • Monitoring is essential for patients with thyroid conditions.

Exocrine Function and Hormones

1. Pancreatic Enzymes (Lipase, Amylase)
   • Fat digestion increases the demand for lipase and other enzymes.
   • In individuals with pancreatic or digestive issues, this can lead to discomfort.
2. Bile Secretion
   • Increased fat intake stimulates bile production.
   • May cause digestive symptoms in people with gallbladder dysfunction.

Drawbacks and Limitations

• Constipation: Due to reduced intake of soluble fiber if vegetable intake is inadequate.
• Keto Breath: Caused by acetone, a type of ketone excreted via the lungs.
• Micronutrient Deficiencies: Risk of insufficient intake of B-vitamins, magnesium, potassium, etc.
• Adherence Challenges: Requires long-term motivation and education.
• Not Suitable for Everyone: Should be used cautiously in patients with advanced kidney disease, gallbladder issues, or during pregnancy.

Clinical Perspective and Patient Guidance

As a clinician or nutrition specialist, dietary recommendations must be individualized based on:

• Metabolic status
• Personal goals (weight loss, diabetes control, sports performance, PCOS, etc.)
• General health and comorbidities
• Psychological readiness and dietary habits

Low-carb and ketogenic diets can be powerful therapeutic tools, especially in clinical settings, when paired with:

• Patient education
• Regular lab monitoring (HbA1c, lipids, thyroid hormones, kidney function)
• Adequate intake of healthy fats, sufficient protein, and micronutrient supplementation as needed

Conclusion

Low-carb and ketogenic diets, when properly applied, can offer substantial benefits for metabolic health, weight management, and even hormonal regulation. However, they require scientific planning, hormonal awareness, and personalized follow-up to be both effective and sustainable. In addition to ketogenic diets, using a variety of diets, such as Fasting Diets , etc., that are planned and presented based on a scientific study of your physical condition, can be of great help in improving your health.