- An in-depth look at the keto diet, its metabolic response, benefits and roles, potential side effects, foods to include, and sample meal plan.
There is no one-size-fits-all eating pattern, which is what can make weight loss and healthy eating so difficult.
Of the many dietary patterns, the ketogenic diet (or keto diet, for short) has been practiced since the 1920s and has a sound basis in physiology and nutrition.
What is the Keto Diet?
In the Standard Ketogenic Diet (SKD), the most widely researched and practiced type:
- Carbohydrates total about 5% of total calorie intake
- Fats replace most of the cut carbs and provide approximately 75% of total calorie intake
- Proteins make up the rest of the needs, about 20% of total calorie intake.
To put this diet into comparison with the typical American diet, the typical American diet is composed of 20-35% fat, 50-70% carbohydrates and 15-20% protein.
The Metabolic Response to the Diet
Carbohydrates are the primary source of energy production in body tissues. When the body is deprived of carbohydrates (an intake of fewer than 50 grams per day), insulin secretion is significantly reduced, and the body starts a breakdown.
Glycogen stores deplete, and the body is forced to go through certain metabolic changes. Two metabolic processes come into action when there is low carbohydrate availability in body tissues: gluconeogenesis (the formation of glucose from substances other carbohydrates – like proteins and fats) and ketogenesis .
Once glucose availability drops further and the production of glucose from proteins and fats (gluconeogenesis) is not able to keep up with the needs of the body:
- Ketogenesis kicks in, providing an alternate source of energy in the form of ketone bodies
- Blood glucose levels remain low, lowering insulin stimulus
- The need for fat and glucose storage drastically lowers
- Other hormonal changes may contribute to an increased breakdown of fats
Metabolism remains in the ketonic state as long as the body is deprived of carbohydrates.
This state (ketosis) is not the same as ketoacidosis, a life-threatening condition where ketone bodies are produced in extremely large concentrations, altering blood pH to an acidotic state.
Ketone bodies that are synthesized in the body can be easily utilized for energy production by the heart, muscle tissue, and kidneys.
They can also cross the blood-brain barrier to provide an alternative source of energy to the brain. Ketone body production depends on several factors:
- Resting basal metabolic rate (BMR)
- Body mass index (BMI)
- Body fat percentage
These factors are why carbohydrate restrictions among individuals – some can reach a state of ketosis at 50 grams of carbohydrates per day while others need to restrict further.
Potential Benefits, Therapeutic Roles of the Ketogenic Diet and Emerging Evidence
There is ample evidence to support the notion that the ketogenic diet can lead to an improvement in some metabolic pathways and have beneficial health effects.
Below are some therapeutic roles of the ketogenic diet as well as emerging evidence:
- There appears to be a reduction in appetite due to higher satiety effects of proteins, effects on appetite control hormones and a possible direct appetite-suppressant action of the ketone bodies.
- There is a reduction in the formation of fat (lipogenesis) and an increase in the breakdown of fats (lipolysis); and greater metabolic efficiency in consuming fats.
- There is an increase in metabolic demands.
Type 2 Diabetes, metabolic syndrome and insulin resistance
- Diabetes, insulin resistance, and metabolic syndrome are all diseases of carbohydrate intolerance and characterized by changes in metabolism, high blood sugar, and impaired insulin function. The ketogenic diet can help with excess fat loss, improvement in glucose control and systemic insulin sensitivity.
- During ketogenesis, signs, and symptoms of insulin resistance improve or often disappear completely.
- Mechanisms of action are not clear; however, a ketogenic diet is considered an established part of an integrative approach, along with drug therapy. Research has shown that the ketogenic diet can cause massive reductions in seizures in epileptic patients.
- Emerging evidence shows that ketogenic diets may also help with other conditions, such as acne, cancer, polycystic ovary syndrome, neurological diseases, Alzheimer’s disease, Parkinson’s disease, brain injuries, and potentially amyotrophic lateral sclerosis (ALS), however more research and evidence is needed.
Potential Side Effects and Cautions
Long-term health implications of the ketogenic diet are not well known due to limited literature.
However, short-term effects, up to 2 years, are well reported. The most common and relatively minor short-term side effects (also known as “keto flu”) of the diet include:
- Nausea, vomiting, constipation
- Headache, fatigue, dizziness
- Difficulty in exercise tolerance
Symptoms usually resolve in a few days to a few weeks and adequate fluid and electrolyte intake can help counter some of the symptoms.
Some of the more long-term adverse effects include hepatic steatosis (fatty liver), hypoproteinemia (abnormally low protein levels in the blood), kidney stones, and vitamin and mineral deficiencies.
People suffering from diabetes and taking insulin or oral hypoglycemic agents can suffer severe hypoglycemia if medications are not appropriately adjusted before initiating the diet.
This diet is also contraindicated in patients with pancreatitis, liver failure, disorders of fat metabolism, primary carnitine deficiency, carnitine palmitoyl transferase deficiency, carnitine translocase deficiency, porphyria, or pyruvate kinase deficiency.
Foods to Shop for:
On the ketogenic diet, there should be a consistent focus on eating unprocessed food, consisting primarily of cruciferous and green leafy vegetables, raw nuts and seeds, eggs, fish, unprocessed animal meats, dairy products and natural plant oils and fats from avocados, coconuts and olives.
Foods should be centered around:
- Eggs: Pastured, organic whole eggs or omega-3-enriched eggs are the best choices.
- Poultry: Chicken and turkey.
- Fatty fish: Wild-caught salmon, herring and mackerel.
- Shellfish: Oysters, shrimp and scallops.
- Meat: Grass-fed beef, venison, pork, organ meats and bison.
- Full-fat dairy: Unsweetened yogurt, butter, heavy cream, and sour cream.
- Full-fat cheese: Cheddar, mozzarella, brie, goat cheese and cream cheese.
- Frozen or fresh berries: Blueberries, raspberries, blackberries and strawberries.
- Healthy fats/oils: Coconut oil, olive oil, avocado oil, coconut butter, ghee, sesame oil and MCT oil.
- Nuts: Almonds, pecans, pistachios, macadamia nuts, walnuts, peanuts.
- Nut butters: Natural peanut butter, almond and cashew butters.
- Seeds: Pumpkin seeds, flaxseeds, sunflower seeds, chia seeds.
- Non-starchy vegetables (fresh or frozen): Mushrooms, cauliflower, broccoli, cabbage, Brussel’s Sprouts, carrots, greens (spinach, kale, sea veggies), peppers, onions, and tomatoes.
- Dark chocolate and cocoa powder: Choose a dark chocolate that contains a minimum of 70% cocoa solids, preferably more.
- Condiments: Sea salt, pepper, salsa, vinegar, lemon juice, fresh herbs and spices, garlic, mustard, hot sauce, pickles, and olives.
- Keto-friendly beverages: Water (toss in lemon, lime, orange slices or fresh mint), sparkling water, unsweetened coffee (flavored with heavy cream), unsweetened green tea, occasional alcohol drink (vodka or tequila mixed with soda water).
- Keto-friendly sweeteners: Stevia, erythritol, inulin, monk fruit, yacon syrup.
Foods that should be avoided include :
- Breads and baked goods: White bread, whole-wheat bread, crackers, cookies, donuts, rolls, etc.
- Sweet and sugary foods: Sugar, ice cream, candy, coconut sugar, maple syrup, honey, agave syrup, dates, agave nectar, blackstrap molasses etc.
- Sweetened beverages
- Grains and grain products: Wheat, rice, oats, tortillas, cereal, etc.
- Beans and legumes: Black beans, chickpeas, lentils, kidney beans, etc.
- Fruit: Bananas, pineapple, mango, citrus, grapes, grapefruit, pears, plums, cherries, etc.
- Starchy vegetables: Corn, peas, potatoes, sweet potatoes, butternut squash, pumpkin, yams, etc.
- High-carb sauces and condiments: Barbecue sauce, sugary salad dressings, various dipping sauces.
- Processed foods
- Unhealthy fats: Vegetable oils (canola and corn oils), peanut oil, margarine, and shortening.
- “Diet” foods: Foods containing artificial sweeteners and some sugar alcohols (aspartame/Equal/NutraSweet, sucralose/Splenda, saccharin/Sweet ‘N Low, xylitol, maltodextrin, polydextrose, truvia), artificial colors, and preservatives.
Sample 1-Week Meal Ideas + Snacks
|MONDAY||Cheese Muffins made with Cheese, Eggs And Your Choice Of Veggies (Onion, Zucchini, Peppers, Tomato, Broccoli, etc.)||Zucchini Grilled Cheese Sandwich||Keto Chicken Enchilada Bowl|
|TUESDAY||Keto Frittata (Made With Any Vegetable You Prefer)||BLT Chicken Salad stuffed Avocados (Using Turkey Bacon, Shredded Chicken, Tomatoes, Cottage Cheese, And Romaine Lettuce)||Grilled Salmon with Spinach Sautéed in Coconut Oil|
|WEDNESDAY||Mushroom Omelet||Lettuce Wrapped Hamburger||Coconut Chicken Curry|
|THURSDAY||Cauliflower Toast Topped With Cheese And Avocado||Tuna Salad with Celery And Tomato atop a Bed Of Greens||Pork And Vegetable stir fry (Using Coconut Aminos, Sesame Oil and Avocado Oil/Olive Oil for stir fry Marinade)|
|FRIDAY||Bell Pepper Stuffed With Cheese And Eggs||Egg Wraps Filled with Turkey, Avocado, Cheese, Hummus, Fresh Herbs and Spices||Meatballs Served with Zucchini Noodles and Parmesan Cheese|
|SATURDAY||Coconut Milk Chia Pudding Topped With Coconut And Almonds||Sheet Pan Eggs with Ground Turkey, Asparagus and Goat Cheese||One-pot Cheesy Taco Skillet (Using Lean Ground Beef, Onion, Peppers, Tomatoes, Homemade Taco Seasoning, Spinach, Shredded Cheddar and Jack Cheese and Green Onions)|
|SUNDAY||Baked Avocado Egg Boats||Shrimp, Asparagus and Avocado Salad||Slow Cooker Pork Roast with Cheesy Broccoli|
- Extra veggies (raw or cooked) with homemade dressing
- ½ avocado with sliced salmon
- Shirataki noodles
- Hard-boiled eggs
- Beef/turkey jerky
- Bone broth
- Cheese roll-ups
- ½ avocado stuffed with chicken salad or tuna salad
- Nuts and cheese
- Homemade keto fat bombs
- Keto smoothie made with coconut milk, cocoa and avocado
The keto diet has been around for several decades, and has been shown to aid in weight loss, have potential benefits for those with diabetes, metabolic syndrome and epilepsy, and possibly reduce risk factors for cardiovascular disease.
Long-term compliance is low and can be a big issue with the diet, and further studies are required to understand disease-specific mechanisms.
A ketogenic diet may be followed for a minimum of 2-3 weeks up to 6-12 months and close monitoring of renal functions while on a ketogenic diet is imperative.
Adding a multivitamin and mineral supplement may be beneficial when practicing this diet as deficiencies can occur.
References1. Kubala J. A keto diet meal plan and menu that can transform your body | Healthline https://www.healthline.com/nutrition/keto-diet-meal-plan-and-menu. Published August 21, 2018. Accessed December 20, 2019.
2. Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. EJCN. 2013; 67:789-796.
3. Veech RL. The therapeutic implications of ketone bodies: The effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism. Prostaglandins Leukot Essent Fatty Acids. 2004; 70: 309–319.
4. Randall R, Groveman S. CPE Monthly: The Ketogenic Diet for Epilepsy - Today's Dietitian Magazine. Today's Dietitian. https://www.todaysdietitian.com/newarchives/0516p46.shtml. Published May 2016. Accessed December 28, 2019.
5. Masood W. Ketogenic Diet. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK499830/?report=classic. Published March 21, 2019. Accessed December 20, 2019.
6. Jagadish S, Payne ET, Wong-Kisiel L, Nickels KC, Eckert S, Wirrell EC. The ketogenic and modified Atkins diet therapy for children with refractory epilepsy of genetic etiology. Pediatr. Neurol. 2019; 94:32-37.
7. Mohorko N, Černelič-Bizjak M, Poklar-Vatovec T, Grom G, Kenig S, Petelin A, Jenko-Pražnikar Z. Weight loss, improved physical performance, cognitive function, eating behavior, and metabolic profile in a 12-week ketogenic diet in obese adults. Nutr Res. 2019; 62:64-77.
8. Westerterp-Plantenga MS, Nieuwenhuizen A, Tome D, Soenen S, Westerterp KR. Dietary protein, weight loss, and weight maintenance. Annu Rev Nutr. 2009; 29:21–41.
9. Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A et al. Ketosis and appetite-mediating nutrients and hormones after weight loss. Eur J Clin Nutr. 2013. doi:10.1038/ejcn.2013.90. 10. Veldhorst M, Smeets A, Soenen S, Hochstenbach-Waelen A, Hursel R, Diepvens K, et al. Protein-induced satiety: effects and mechanisms of different proteins. Physiol Behav. 2008; 94:300–307.
11. Johnstone AM, Horgan GW, Murison SD, Bremner DM, Lobley GE. Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum. Am J Clin Nutr. 2008; 87:44–55.
12. Veldhorst MA, Westerterp-Plantenga MS, Westerterp KR. Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet. Am J Clin Nutr. 2009; 90:519–526.
13. Cahill Jr GF. Fuel metabolism in starvation. Annu Rev Nutr. 2006; 26:1–22.
14. Paoli A, Grimaldi K, Bianco A, Lodi A, Cenci L, Parmagnani A. Medium term effects of a ketogenic diet and a Mediterranean diet on resting energy expenditure and respiratory ratio. BMC Proceedings. 2012; 6(Suppl 3): P37.
15. Paoli A, Cenci L, Fancelli M, Parmagnani A, Fratter A, Cucchi A et al. Ketogenic diet and phytoextracts comparison of the efficacy of Mediterranean, zone and tisanoreica diet on some health risk factors. Agro Food Ind Hi-Tech. 2010; 21:24.
16. Feinman RD, Fine EJ. Nonequilibrium thermodynamics and energy efficiency in weight loss diets. Theor Biol Med Model. 2007; 4:27.
17. Fine EJ, Feinman RD. Thermodynamics of weight-loss diets. Nutr Metab (Lond). 2004; 1:15.
18. Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low-fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab. 2003; 88:1617–1623.
19. Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med. 2008; 359:229–241.
20. Volek JS, Phinney SD, Forsythe CE, Quann EE, Wood RJ, Puglisi MJ et al. Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low-fat diet. Lipids. 2009; 44:297–309.
21. Kossoff E. The fat is in the fire: ketogenic diet for refractory status epilepticus. Epilepsy Curr. 2011; 11:88–89.
22. Noakes TD, Windt J. Evidence that supports the prescription of low-carbohydrate high-fat diets: a narrative review. British Journal of Sports Medicine. 2017; 51:133-139.
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Meghan is a registered dietitian nutritionist in private practice in Minneapolis, Minnesota. Her areas of expertise include functional nutrition and digestive health.