The Ketogenic Diet: Principles, Benefits, Risks, and GLP-1 Medication Considerations
Curious about the ketogenic (keto) diet and how it might interact with modern weight loss medications like GLP-1 receptor agonists? Here’s what you need to know.
What Is the Keto Diet?
The ketogenic diet is a high-fat, moderate-protein, and very low-carbohydrate eating plan. Typical macronutrient ratios are:
70–80% fat
10–20% protein
5–10% carbohydrates (usually less than 50 grams per day)
This approach aims to induce ketosis, a metabolic state where the body shifts from using glucose as its primary energy source to burning fat and producing ketones for fuel.
Potential Benefits and Applications
Clinical research suggests the keto diet may benefit:
Weight Management: Keto can be effective for short-term weight loss, often resulting in rapid initial reductions in body weight.
Type 2 Diabetes: Studies show improved glycemic control and reduced medication needs in some individuals with type 2 diabetes.
Epilepsy: The diet remains an established treatment for drug-resistant epilepsy, especially in children.
Neurological Disorders: Emerging evidence suggests potential benefits in Alzheimer’s, Parkinson’s, and other neurodegenerative diseases.
Cancer: Some studies indicate anti-tumor effects and possible enhancement of certain cancer treatments, though more research is needed.
Combining the Keto Diet with GLP-1 Medications
For individuals following the keto diet and taking GLP-1 receptor agonists (e.g., semaglutide, liraglutide), there are unique considerations to optimize health outcomes. These medications, often prescribed for weight loss or diabetes management, enhance satiety and regulate blood sugar levels. When paired with a ketogenic eating pattern, careful planning is required to balance nutrient intake and manage potential side effects:
Risk of Deficiencies:
The keto diet excludes grains, legumes, and most fruits—key sources of fiber, vitamins, and minerals. GLP-1 medications can further suppress appetite, increasing the risk of deficiencies in magnesium, potassium, and vitamin C.
Solution: Prioritize keto-friendly nutrient powerhouses such as spinach and avocado (magnesium, potassium), bell peppers and Brussels sprouts (vitamin C), and bone broth (collagen, electrolytes). Consider a low-carb electrolyte supplement if dietary intake falls short.
Protein Intake for Satiety and Muscle Preservation:
Both keto and GLP-1 medications promote fat loss, but inadequate protein intake may accelerate muscle wasting. Studies show protein needs increase by 20–30% during rapid weight loss phases.
Tip: Aim for 1.2–1.5g of protein per kg of ideal body weight daily. Opt for fatty fish (salmon, mackerel), pasture-raised eggs, and collagen peptides to support muscle mass and gut health.
Digestive Health:
GLP-1 medications can cause nausea, bloating, or constipation. The low fiber content of the keto diet may compound these effects.
Recommendation: Gradually increase fiber intake with non-starchy vegetables like zucchini and spinach, and consider chia seeds or flaxmeal. Stay hydrated and consider fermented foods like sauerkraut for gut health.
Balancing Fats:
While keto emphasizes high fat intake, GLP-1 medications enhance insulin sensitivity—a combination that requires strategic fat selection to avoid exacerbating cardiovascular risks.
Guidance: Focus on monounsaturated fats (avocados, olive oil) and omega-3s (salmon, walnuts) while moderating saturated fat intake from sources like coconut oil and processed meats.
Blood Sugar Stability:
Keto stabilizes glucose, but GLP-1 medications can cause hypoglycemia in non-diabetic users.
Advice: Check fasting glucose weekly, keep carbohydrate intake ≥30g/day from non-starchy vegetables, and carry glucose tabs if taking insulin or sulfonylureas.
Sustainability:
Both the keto diet and GLP-1 medications require a commitment for lasting results. Strict adherence to keto principles can be challenging over time.
Flexibility: Consider a modified “Keto Plus” approach by allowing 50–70g net carbs/day from berries, carrots, or squash if metabolic goals are met. Some may benefit from cyclical ketosis (5 keto days + 2 moderate-carb days) for sustainability.
Potential Risks and Considerations
Clinical studies suggest the keto diet may include the following considerations:
Nutrient Gaps: Restriction of fruits, legumes, and whole grains can lead to deficiencies in vitamins, minerals, and fiber.
Transition Effects: Many experience “keto flu” (fatigue, headaches) during the first 1–2 weeks.
Electrolyte Imbalance: Keto’s diuretic effect and GLP-1’s slowed gastric emptying increase dehydration risks.
Long-Term Effects: The diet is high in saturated fat, which may increase LDL cholesterol in some people; long-term effects on heart health are still under study.
Cost: High-quality fats and proteins can be more expensive than standard dietary staples.
Keto-Friendly and Excluded Foods
-
Included: Fish and seafood (salmon, sardines, mackerel, tuna), meat and poultry (beef, chicken, turkey, pork), eggs
Excluded: Grains, legumes, most processed meats with added sugars -
Included: Avocados and avocado oil, olive oil, butter and ghee, nuts and seeds (macadamia, almonds, walnuts)
Excluded: Most vegetable oils (canola, corn, soybean), margarine, shortening -
Included: Leafy greens (spinach, kale, arugula), broccoli, cauliflower, zucchini, bell peppers, berries (in moderation)
Excluded: Starchy vegetables (potatoes, corn), high-sugar fruits (bananas, grapes) -
Included: Full-fat cheese (cheddar, brie, goat cheese), heavy cream, full-fat yogurt (in moderation)
Excluded: Low-fat dairy, sweetened yogurts
A Day of Keto Meals
Breakfast
Mushroom omelet with sautéed greens
Full-fat yogurt topped with keto granola
Bacon and avocado frittata
Lunch
Bunless burger topped with cheese, mushrooms, and avocado on a bed of greens
Crab stuffed avocados
Caesar salad with chicken
Dinner
Grilled salmon with spinach sautéed in sesame oil
Chicken Alfredo with spaghetti squash
Keto beef stroganoff with cauliflower rice
Snacks
Hardboiled eggs
Celery sticks with cream cheese dip
Macadamia nuts or almonds
Cheese rollups
Historical Context
The ketogenic diet was developed in the 1920s as a treatment for pediatric epilepsy. Dr. Russell Wilder at the Mayo Clinic coined the term "ketogenic diet" and demonstrated its efficacy in reducing seizure frequency and intensity. Its use declined with the advent of antiepileptic drugs but resurged in the 1970s for weight loss and metabolic health.
Scientific Basis and Metabolic Effects
Restricting carbohydrates to less than 50 grams daily decreases insulin secretion, leading the body into a catabolic state. This triggers:
Gluconeogenesis: Production of glucose from non-carbohydrate sources.
Ketogenesis: Formation of ketone bodies from fatty acids.
These metabolic changes underpin the diet’s effects on weight loss and potential health benefits.
Leading Keto Experts
Dr. Eric Westman: Associate Professor of Medicine at Duke University, author of "End Your Carb Confusion," and researcher on low-carb diets and obesity.
Dr. Dominic D’Agostino: Professor at the University of South Florida, leading researcher in ketogenic diets and metabolic therapies, especially for cancer and neurological disorders.
Dr. Stephen Phinney & Dr. Jeff Volek: Coauthors of "The Art and Science of Low Carbohydrate Living," pioneers in ketogenic diet research.
Dr. Jason Fung: Author of "The Obesity Code," advocate for ketogenic diets and intermittent fasting for metabolic health.
Essential Keto Cookbooks
The Complete Ketogenic Diet for Beginners by Amy Ramos: A comprehensive introduction to the ketogenic diet, featuring evidence-based information and simple recipes.
The New Atkins for a New You Cookbook by Colette Heimowitz: Offers low-carb recipes along with detailed nutritional information.
The Keto Reset Diet by Mark Sisson: Provides scientific explanations, meal plans, and a variety of recipes to support a ketogenic lifestyle.
The Ultimate Guide to Keto Baking by Carolyn Ketchum: Focuses on keto-friendly baking with thoroughly tested recipes.
Simply Keto by Suzanne Ryan: Combines personal insights with meal plans and recipes to guide readers through the ketogenic diet.
Short-Term vs. Long-Term Use
Short-Term (1–3 months): Often used for rapid weight loss or to "reset" metabolism, with benefits for insulin sensitivity and initial weight reduction.
Long-Term: Some maintain a ketogenic lifestyle for years, but long-term adherence can be challenging and may increase risk for nutrient deficiencies and changes in gut microbiota. Many adopt a “Keto Plus” approach, reintroducing small amounts of nutrient-dense carbohydrates for sustainability.
Conclusion
The ketogenic diet offers a high-fat, low-carbohydrate approach that may support metabolic health, especially when thoughtfully combined with GLP-1 medications. However, it’s important to plan carefully to avoid nutrient gaps, manage side effects, and ensure long-term sustainability. Consult with a healthcare provider or registered dietitian before making significant dietary changes.
Have you tried the keto diet or GLP-1 medications? Share your experiences with us at hello@foodinformed.com
Resources:
Harvard Health: Should you try the keto diet?
Nature: The ketogenic diet has the potential to decrease all-cause mortality
Northwestern Medicine: Epilepsy and the Keto Diet
News-Medical: Keto controversy? Experts say it's here to stay
Good Housekeeping: 10 Best Keto Cookbooks for a Low-Carb Lifestyle
Frontiers in Nutrition: Symptoms during initiation of a ketogenic diet: a scoping review of the literature
Journal of Clinical Endocrinology & Metabolism: Low-carb diet may benefit beta-cell function in patients with type 2 diabetes