The ketogenic diet, also known as the keto diet is a low-carb, high-fat diet designed to help your body burn fat with great efficiency. When you dramatically reduce your carbohydrate intake and replace the calories with foods high in fat, your body goes into ketosis.
The ketogenic diet plan was introduced by physicians in the 1920s, when they noted that children with epilepsy had improved seizure control after 2–3 days on a what was coined a ketogenic diet.2
From a metabolic perspective, eating a low-carb, high-fat diet mimics metabolism with reduced negative side effects.2
The diet fell out of favor in the medical community from the late 1930s until the 1970s when drugs were introduced for the management of epilepsy.2 It regained popularity in the 1980s and has gradually entered the mainstream awareness of diet programs since.
What is keto today? The science behind ketogenic diet plans remain largely unchanged. But with a wider variety of foods available, it is easier than ever to follow. Today, there are four common varieties of keto diets:
- Standard ketogenic diet (SKD), which is commonly described as 75% fat, 20% protein and, 5% carbohydrates.
- Cyclical ketogenic diet (CKD), which involves cycles of eating higher carbs for short periods. For example, 5 ketogenic days followed by 2 high-carb days.
- Targeted ketogenic diet (TKD), which is characterized as the allowance of additional carbohydrates around workouts.
- High-protein ketogenic diet, which is like the standard ketogenic diet except it includes more protein. The common ratio is 60% fat, 35% protein, and 5% carbs.
Most clinical research focuses on the standard and high-protein ketogenic diets. The cyclical and targeted ketogenic diets are relatively new and used mostly by athletes and bodybuilders.
How to Do the Ketogenic Diet
The key to following a ketogenic diet meal plan is planning. Make sure you have a good supply of acceptable food choices that you enjoy eating. Some people self-report needing to clear their kitchen of carbohydrates to reduce temptation.
If you are following a ketosis diet plan, make sure to limit carbohydrate intake to 50 grams per day. Limiting carbohydrate intake will force the body to rely on fat for energy. There are no special shakes, products or tools required for the keto diet but some people buy a supply of ketone testing strips from a pharmacy to help them identify when their body is in ketosis.
Ketogenic Diet Symptoms & Safety
As previously mentioned, the natural and expected outcome of eating a low-carb, high-fat diet is ketosis, the key ketogenic diet mechanism.
Originally, the ketogenic diet was developed as a medical treatment. When followed for a short period of time, there have been few reports of any ill-effects. Of all possible side effects, ketogenic diet followers cite “bad breath” as the most immediate and noticeable symptom.
Having low blood sugar on ketogenic diet plans is another common side effect, which may happen in the beginning of the diet, according to anecdotal reports. Fatigue, increased urination, light-headedness and decreased appetite are other common self-reported side effects of the keto diet.
Long-term adherence to a ketogenic diet should only be done under a doctor’s supervision. Pancreatitis and other adverse events have been noted in clinical studies involving adults and children.4,5 In rare cases, extended use of the keto diet in people with abnormal insulin function can lead to ketoacidosis.
Ketogenic Diet Foods
The key to success is knowing what to eat on the ketogenic diet. Below, Better Health Organization has compiled an easy to follow list of keto foods. Whenever possible, users are encouraged to choose whole, unprocessed items.
- Any cut of beef, pork, chicken, turkey, lamb, and venison
- Salmon, tuna, trout, snapper, halibut, cod
- Lobster, clams, oysters, crab, abalone
- Sour cream
Nuts and Seeds
- Cashews (occasionally, in moderation)
- Ground flaxseed
- Pistachios (occasionally, in moderation)
- Pumpkin seeds
- Sesame seeds
- Sunflower seeds
- All leafy (salad) greens
- Bamboo shoots
- Broccoli (in moderation)
- Cauliflower (in moderation)
- Kale (in moderation)
- Spaghetti squash (in moderation)
- Occasional and small portions of strawberries, blueberries, raspberries, or blackberries
- Olive oil
- Coconut oil
- Sesame oil
- Avocado oil
- Coffee (with cream, no sugar)
- Tea (any kind, including black tea and rooibos tea)
- Ketogenic diet shakes (e.g. Blend of almond milk, cocoa powder, and almond butter)
Condiments and Spices
- Mustard (in moderation)
- Horseradish (in moderation)
If you are looking to following a vegan ketogenic diet, the above keto diet foods list can be modified. While tempeh and seitan are keto-approved, users should consume tofu in moderation.
Ketogenic Diet Cancer
Many people report feeling better on a ketogenic diet when battling cancer. Some go as far as to claim, “the ketogenic diet cured my cancer”. There is ongoing research into the benefits of the keto diet, including how it might help prevent or combat cancer and the effects of treatment. However, none of the existing ketogenic diet studies have shown a correlation between the keto diet and complete cancer remission.
As a result, some doctors recommend the ketogenic diet for cancer treatment as a complimentary form of management. Anecdotal reports note that the cyclical or CKD version of the diet is tolerated best.
Ketogenic Diet and Colon Cancer
In a recent animal study, subjects who had colon cancer were fed a ketogenic diet. Results showed the high-fat diet delayed the growth of tumours. Although results are promising, more research is necessary to understand how the keto diet can be applied in human colon cancer treatment.7
Ketogenic Diet and Prostate Cancer
Clinical research on this branch of oncology recognizes evidence that a high-fat, low-carb diet may help delay the growth of cancerous tumors.8 Additionally, ketones have been shown to inhibit prostate cancer growth in preclinical models. While human studies have not confirmed these results, a ketogenic diet clinical trial that started in 2017 might offer new insights.9
Ketogenic Diet and Glioblastoma
In 2014, the effects of a ketogenic diet on glioblastoma patients were studied. The researchers found that with the ketogenic diet, glioblastoma multiforme patients’ blood glucose levels decreased, which resulted in improvements in clinical outcomes. The diet was considered well tolerated during radiation and chemotherapy and successful enough to warrant larger studies.10
Ketogenic Diet and Gastric Cancer
While research on gastric cancer and the ketogenic diet is limited, preliminary animal studies yield promising results.
In a 2008 study, animal subjects with gastric adenocarcinoma were fed either a high-protein ketogenic diet or standard diet. Results show tumours in subjects following the keto diet grew at a delayed rate.11
More clinical studies are required before a low-carb, high-fat diet can be considered a complimentary cancer treatment.
Ketogenic Diet Weight Loss
Many people use the ketogenic diet to lose weight. But is it an effective weight loss tool? Research shows that reducing carbohydrates to the point of ketosis and maintaining high protein intake can reduce appetite, which can help with weight loss.12
Among the scientific community, there is practically no dispute that low-carbohydrate diets result in weight loss. The ketogenic diet plan is considered effective because of several factors including, the satiating effect of protein, increased conversion of fat to energy, limited food choices (leading to lower calorie intake), and the appetite suppressing effect of ketosis.13
There is some evidence that following a ketogenic diet plan is more appropriate for significantly overweight or obese people. Individuals within normal weight ranges have less fat to convert to energy and may risk losing muscle mass if they follow a ketogenic diet weight loss meal plan for too long.13
Ketogenic Diet Benefits
The ketogenic diet benefits include:
1. Possible weight loss
2. Anti-tumour activity
3. Lower blood pressure
4. Improve epilepsy symptoms
5. Support pancreas health
6. Lower cholesterol
7. Manage diabetes symptoms
8. Support heart health
9. Possibly delay Alzheimer’s
Most benefits of the ketogenic diet are at the metabolic level. Yet, their effects are measurable and can translate into fewer noticeable health issues and improved wellbeing. Below, we take a look at the top benefits of following the keto diet plan.
Ketogenic Diet and High Blood Pressure
Research into ways to manage cardiovascular health indicates that following a high-fat, low-carb diet may lead to a more normal and consistent blood pressure.14
High intakes of carbohydrates can spike insulin levels in the body. Chronic, high levels of insulin may lead to insulin resistance overtime.15
On a keto diet, the release of glucose into the blood is slow and steady. This “trickling” of glucose doesn’t flood the blood with insulin. As a result, there is little to no excess of insulin in the blood.
Ketogenic Diet and Seizures
A key aspect of a ketogenic diet is the increased production of glycogen. Scientists are continuing to discover the importance of glycogen to brain health.16 One study showed that increased brain glycogen could delay the onset of seizures.17
This builds on the history of prescribing a keto diet for children with epilepsy. In recent years, more physicians are also prescribing a ketogenic diet for adults with epilepsy.
Ketogenic Diet Pancreatitis Support
Pancreatitis is inflammation of the pancreas. Among other functions, the pancreas secretes insulin into the bloodstream to help control how the body uses food for energy.
The low-carbohydrate factor of the ketogenic diet is believed by some to help reduce insulin spikes and stress on the pancreas.
Ketogenic Diet and Cholesterol
There is some evidence that following a ketogenic diet can help people attain and maintain healthy cholesterol levels.
In a 2006 study, researchers studied people who were obese and had high levels of total cholesterol. The researchers found that the subjects’ total cholesterol levels decreased after being on a ketogenic diet for 56 weeks.18
Ketogenic Diet and Diabetes
A ketogenic diet program may be an alternative way to manage blood sugar and insulin levels without medication.
In a clinical study, researchers found that subjects with obesity and type-2 diabetes who were placed on a standard ketogenic diet had significant improvements in glycemic control and medication reduction. Results were more significant than subjects who were placed on a low-glycemic diet.19
Ketogenic Diet and Heart Disease and Stroke
With the ketogenic diet, science has consistently shown that common markers of heart disease and stroke, such as high cholesterol and blood pressure may be effectively lowered.15,18
Ketogenic Diet and Alzheimer’s
In a 2005 animal study, researchers found that a ketogenic diet reduced amyloid beta levels by 25%.22 Amyloid beta is an amino acid that plays a role in the development of Alzheimer’s disease.23
Scientific Research Referenced in this Article
- Fukao, T., Lopaschuk, G.D., Mitchell, G.A. (2004). Pathways and control of ketone body metabolism: on the fringe of lipid biochemistry. Prostaglandins, Leukotrienes, and Essential Fatty Acids. 70(3). 243-51. DOI: 10.1016/j.plefa.2003.11.001
- Wheless, J.W. (2008). History of the ketogenic diet. Epilepsia. 49. 3-5. http://dx.doi.org/10.1111/j.1528-1167.2008.01821.x
- Musa-Veloso, K., Likhodii, S.S., Cunnane, S.C. (2002). Breath acetone is a reliable indicator of ketosis in adults consuming ketogenic meals. American Journal of Clinical Nutrition. 76(1). 65-70. https://www.ncbi.nlm.nih.gov/pubmed/12081817
- Stewart, W.A., Gordon, K., Camfield, P. (2001). Acute Pancreatitis Causing Death in a Child on the Ketogenic Diet. Journal of Child Neurology. 16(9). 682-682. https://doi.org/10.1177/088307380101600910
- Ballaban-Gil, K., Callahan, C., O’Dell, C., Pappo, M., Moshé, S., Shinnar, S. (1998). Complications of the ketogenic diet. Epilepsia. 39(7). 744-8. https://www.ncbi.nlm.nih.gov/pubmed/9670903
- Schmidt, M., Pfetzer, N., Schwab, M., Strauss, I., Kämmerer, U. (2011). Effects of a ketogenic diet on the quality of life in 16 patients with advanced cancer: A pilot trial. Nutrition & Metabolism. https://doi.org/10.1186/1743-7075-8-54
- Hao, G-W., Chen, Y-S., He, D-M., Wang, H-Y., Wu, G-H., Zhang, B. (2015). Growth of human colon cancer cells in nude mice is delayed by ketogenic diet with or without omega-3 fatty acids and medium-chain triglycerides. Asian Pacific Journal of Cancer Prevention. 16(5). 2016-2068. DOI: http://dx.doi.org/10.7314/APJCP.2015.16.5.2061
- Mavropoulos, J.C., Isaacs, W.B., Pizzo, S.V., Freedland, S.J. (2006). Is there a role for a low-carbohydrate ketogenic diet in the management of prostate cancer? Urology. 68(1). 15-18. http://dx.doi.org/10.1016/j.urology.2006.03.073
- “Ketogenic Diet and Prostate Cancer Surveillance Pilot (GCC 1717)”. U.S. National Library of Medicine Clinical Trials. July 31, 2017. https://clinicaltrials.gov/ct2/show/NCT03194516
- Champ, C.E., Palmer, J.D., Volek, J.S. et al. (2014). Targeting metabolism with a ketogenic diet during the treatment of glioblastoma multiforme. Journal of Neuro-Oncology. 117(1). 125-131. https://doi.org/10.1007/s11060-014-1362-0
- Otto, C., Kaemmerer, U., Illert, B., Muehling, B., Pfetzer, N., Wittig, R., Ullrich Voelker, H., Thiede, A., Coy, J.F. (2008). Growth of human gastric cancer cells in nude mice is delayed by a ketogenic diet supplemented with omega-3 fatty acids and medium-chain triglycerides. BMC Cancer. 8(122). https://doi.org/10.1186/1471-2407-8-122
- Johnstone, A.M., Horgan, G.W., Murison, S.D., Bremner, D.M., Lobley, G.E. (2008). Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum 1,2,3. American Society for Clinical Nutrition. 87(1). 44-55. http://ajcn.nutrition.org/content/87/1/44.short
- Malik, V.S., Hu, F.B. (2007). Popular weight-loss diets: from evidence to practice. Nature Clinical Practice Cardiovascular Medicine. 4(34). http://dx.doi.org/10.1038/ncpcardio0726
- Stern, L., Iqbal, N., Seshadri, P., Chicano, K.L., Daily, D.A., McGrory, J., Williams, M., Gracely, E.J., Samaha, F.F. (2004). The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial. Annals of Internal Medicine. 140(10). 778-85. https://www.ncbi.nlm.nih.gov/pubmed/15148064
- Salvetti, A., Brogi, G., Di Legge, V., Bernini, G.P. (1993). The inter-relationship between insulin resistance and hypertension. 46(2). 149-159. https://www.ncbi.nlm.nih.gov/pubmed/7512468
- Falkowska, A., Gutowska, I., Goschorska, M., Nowacki, P., Chlubek, D., & Baranowska-Bosiacka, I. (2015). Energy Metabolism of the Brain, Including the Cooperation between Astrocytes and Neurons, Especially in the Context of Glycogen Metabolism. International Journal of Molecular Sciences. 16(11), 25959–25981. http://doi.org/10.3390/ijms161125939
- Bernard-Helary, K., Lapouble, E., Ardourel, M., Hévor, T., Cloix, J-F. (2000). Correlation between brain glycogen and convulsive state in mice submitted to methionine sulfoximine. Life Sciences. 67(14). 1773-1781. https://doi.org/10.1016/S0024-3205(00)00756-6
- Dashti, H.M., Al-Zaid, N.S., Mathew, T.C. et al. (2006). Long Term Effects of Ketogenic Diet in Obese Subjects with High Cholesterol Level. Molecular and Cellular Biochemistry. 286(1). https://doi.org/10.1007/s11010-005-9001-x
- Westman, E.C., Yancy, W.S., Mavropoulos, J.C., Marquart, M., McDuffie, J.R. (2008). The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutrition & Metabolism. 36(5). https://doi.org/10.1186/1743-7075-5-36
- Law, M.R., Wald, N.J., Rudnicka, A.R. (2003). Quantifying effect of statins on low density lipoprotein cholesterol, ischaemic heart disease, and stroke: systematic review and meta-analysis. BMJ. 326(7404). 1423. http://www.bmj.com/content/326/7404/1423
- Franklin, S.S., Larson, M.G., Khan, S.A., Wong, Nathan D., Leip, E.P., Kannel, W.B., Levy, D. (2001). Does the Relation of Blood Pressure to Coronary Heart Disease Risk Change With Aging? Circulation. 103. 1245-1249. https://doi.org/10.1161/01.CIR.103.9.1245
- Van der Auwera, I., Wera, S., Van Leuven, F., Henderson, S.T. (2005). A ketogenic diet reduces amyloid beta 40 and 42 in a mouse model of Alzheimer’s disease. Nutrition & Metabolism. 28(21). https://doi.org/10.1186/1743-7075-2-28
- Schmechel, D., Saunders, A., Strittmatter, W., Crain, B., Hulette, C., Joo, S., Pericak-Vance, M., Goldgaber, D., Roses, A., (1993). Increased amyloid beta-peptide deposition in cerebral cortex as a consequence of apolipoprotein E genotype in late-onset Alzheimer disease. Proceedings of the National Academy of Sciences. 90(20). 9649-9653. http://www.pnas.org/content/90/20/9649