Is anyone as confused as I am when thinking about the different diets out there?
This one says to eat according to your blood type, while this one recommends eating like cavemen. In 2013, the Paleo diet was the most googled diet out there. Did anyone tell the Paleos that cavemen barely lived to thirty? What about the keto diet? That one regained popularity in 2016. Why would we want to avoid fruits, grains and beans when they’re among the foods most associated with health and longevity? You probably know someone who had great results with keto, but is it just me, or is it slightly suspicious telling people to avoid well studied health foods while doubling down on bacon and red meat, which are confirmed class 1 carcinogens?
Never has a weight loss diet created so much controversy and division. The ketogenic diet has been referred to as the best diet for health and weight loss, and has been also called a dietary disaster waiting to happen. Who should we believe? No wonder why people are so confused. People who love bacon and butter will likely love keto, and vegans will probably find something wrong with eating mostly animal products. Let’s leave our egos at the door and see what the science says are the pros and cons of keto and then you can decide if it’s something you want to do.
I can already sense haters from both sides getting agitated. My goal here isn’t to tell anyone how to eat, but to inform people of the pros and cons of their choices and then let them make an informed decision based on the latest science. If the balance of evidence says that keto kills, that’s what I’ll report, and if it says that keto is king, I’ll gladly report that too. As a disclaimer, when I’m talking about the ketogenic diet, I’m referring to the standard typical keto diet where fat is mostly derived from animal products. There’s such a thing as a plant-based vegan keto diet, and that is a totally different beast altogether. I’ll talk about this version of keto shortly.
One of the major benefits of this diet is that the ketogenic diet does cause a rapid initial weight loss. It can also lead to quick improvement of metabolic markers, like HbA1C, cholesterol and blood pressure. That’s the major advantage of the keto diet.
Let’s review the mechanisms responsible for the weight loss and improved health markers, and the long term health effects of this pattern of eating. I‘ll discuss the different types of keto diet, including the standard or typical keto diet, and the vegan or plant-based keto diet.
Check out the following foods permitted on a keto diet. The issue isn’t the types of food, but more the quantities permitted. With less than 20 grams of carbs per day, most of the foods “permitted” in the food pyramid must be severely restricted to respect the strict carb limit imposed. To put things into context, a banana would have more carbs than the total amount permitted in a single day.
The diet pretty much says: “Eat fat. Eat meat, poultry, eggs and fish. The fattier the better. Eat non-starchy vegetables”. Sounds healthy doesn’t it? But if you’re tempted to comment that the pyramid does contain berries, please note that to achieve ketosis, you will have to consume less than 20 grams of carbs per day. A cup of berries and you’re pretty much half way there already. To put things in perspective, I eat more than 300 grams of carbs per day on a whole food plant-based diet. Doing this, I have reversed 3 allergic conditions, loss 10 pounds of fat and gained it in muscle, as well as increased my athletic performance exponentially, exactly like the studies report.
This review is based on science, and I know this will upset some of you. That’s why my “opinion” will be based on the most comprehensive and in depth review of the available ketogenic diet data to date. More than 120 publications were reviewed and analyzed in order to formulate these conclusions. So let’s get down to business.
WHAT IS A KETO DIET?
A keto diet is a sub-type of low carb diet. Some low carb diets are still high enough in carbs (or protein that can be turned into glucose) that ketosis is not achieved with them. In fact, in keto, carbohydrate intake is so low, that it tricks the body into thinking it‘s in a state of starvation and famine, and turns on our body’s survival mechanisms, in a last ditch effort to keep you alive.
Carbohydrates get turned into glucose which is our primary and preferred source of fuel. Since carbs are practically non-existent on a keto diet, the body will switch into starvation mode and start metabolizing our muscle’s protein to turn it into glucose, and will switch our metabolism towards fat burning. Using fat for fuel produces ketones as a byproduct, and the state of having excessive ketones in our blood is called “ketosis”. Some low-carb diets focus on getting calories from protein and in this case, a state of ketosis can be avoided, since protein can be turned into glucose by our body. The ”real“ keto diet focuses on getting most of our calories from fat, in order to achieve true ketosis, and requires super low intakes of protein and carbohydrates. Basically, you’re eating mainly fat. Keto proponents do recommend avoiding refined or processed foods which are rich in unhealthy carbs, and that’s one thing we both agree on.
The keto diet was originally used as a treatment for refractory epilepsy in children. Its new found glory for weight loss has now been studied extensively and I’m happy to report the conclusions.
Basically, the keto premise is as follows: if the body doesn’t have access to its preferred fuel (glucose), our glycogen stores (glucose chains stored in our muscles and liver as an energy backup) are depleted first. Our body switches to fat as its primary fuel source. That produces ketones as a byproduct, and the body enters an altered metabolic state called “ketosis”.
How do we achieve ketosis?
To be in ketosis, one must use fat as a primary source of energy. To accomplish this, you must limit your carbohydrate intake to less than 20-50 grams per day (a banana contains about 25-30 grams). That means that many “low carb” diets can’t be called keto diets since the amounts of carbs, even if they’re low, aren’t low enough to achieve ketosis. Same thing goes for “low-carb, high-protein” diets. Most don’t achieve ketosis with this diet, since protein is readily available to get turned into glucose, and in this scenario, glucose, not fat or ketones, remains the main source of fuel, thus preventing ketosis. This means that many people eating low carb diets are falsely calling them keto diets. To confirm ketosis, one must measure their ketones to confirm their presence. In keto studies, ketosis is confirmed by measuring ketones in our urine, blood, or ketones in our breath. Urinary dipsticks are readily available to measure ketones at home for those motivated to do so. Without ketosis, low carb diets achieve weight loss exactly like every other diet, through a calorie deficit.
Excessive protein intake must also be avoided for ketosis because protein is readily turned into glucose since it’s our brain‘s primary fuel source. Once in ketosis, it is believed that the ketone bodies will induce a decrease in appetite, leading to calorie deficits that promote weight loss. It takes a few days to achieve ketosis. The switch may be accompanied with various symptoms like brain fog, drowsiness, headaches, nausea and constipation, called the keto flu. These symptoms subside in 3 to 7 days, and then the magic happens.
You’re in ketosis, now what?
Once ketosis has been achieved, and the body switches to fat burning, that’s when the pounds start to come off, but not in the way you’d expect. The super quick weight loss that happens with keto is probably the main motivating factor that attracts people to this way of eating. How is this possible, since the calorie deficit doesn’t seem to account for the total weight loss?
Our muscles are able to store about 2000 calories worth of glucose in the form of glycogen. If you’ve read my previous articles, then you know that 1 gram of carbs equals 4 calories, so 2000 calories equates to 500 grams. Each gram of carbs carries with it about 3 grams of water. So that means we can carry 500 grams of glucose and 1500 grams of water in our muscles. Add these two together and you have almost 2 kilograms, or 4.5 pounds total. As soon as we stop consuming carbs,
our bodies will deplete our glycogen stores before resorting to fat burning. This explains the 2-3 day delay most have before achieving ketosis. It also explains the super quick weight loss that encourages most keto users to pursue this seemingly magical weight loss diet. The initial rapid weight loss is mostly water, glucose and muscle, not fat. This has been proven in well designed metabolic ward studies, where people are admitted in a hospital setting and fed by the study’s designers, making it possible to control every other factor that could influence results. The exact opposite is true when on a low-fat plant-based diet, where most of the weight loss is predominantly from actual body fat.
After the initial water and glucose depletion, does your body become a fat burning machine? It doesn’t really have a choice, except that it will mostly burn dietary fat, not stored fat. I’m assuming that if you’re on a diet, body fat loss is what you’re looking for. Recent meta-analysis have shown that weight loss seen in the keto diet was similar to any other diet, and concluded that the two main factors that lead to weight loss with any diet were calorie deficits and diet adherence, and not a particular macronutrient split.
So I’m not saying the keto diet doesn’t work. I’m saying that the initial weight loss is mostly water and glucose stores, and not fat. I’m also saying that longer term studies show that it works as well as any other weight loss diet promoting a calorie deficit. Adherence is an important issue with maintaining a keto diet, and this is shown by the high drop-out rates in studies.
Is the keto diet safe?
Regularly, many leading scientists are brought together to rank different diets from 1 to 40. In 2018, the US News best diet rankings found the keto diet to be tied for 40th, last place, in terms of overall diets, and was 40th, dead last, in terms of diets for healthy eating. Why? Because the diet is extremely high in saturated fats, and puts the dieter at extremely high risk for nutritional deficiencies. Oh and did I fail to mention all the severe adverse effects?
Although keto works as well as any other diet promoting a calorie deficit, proper adherence seems to be the main issue. Let’s say sticking to this pattern of eating isn’t an issue for you. Should you do it long term?
People assume that if a diet contributes to weight loss, then it’s automatically healthy. Although most instances of weight loss do lead to a favourable metabolic profile (measures of blood sugar, cholesterol and blood pressure), it’s not always the case. That’s one of the reasons why it’s very difficult to tease out the effects of a keto diet. Cholesterol usually goes down with weight loss, but in some people on the keto diet, even with considerable weight loss, their metabolic profile gets worse. Let’s see what the latest science says.
Keto and cholesterol
Some people will have improved metabolic profiles on keto diets. It is thought that this would be the result of weight loss. Losing weight from any cause, including cancer, will usually improve cholesterol, and this is routinely seen with the keto diet. Remember that eating saturated fats found in animal products has been shown to increase LDL (bad cholesterol), and even after significant weight loss on the keto diet, some actually see worsening of their cholesterol, a finding that should raise a red flag. Losing weight is supposed to be healthy, but this isn’t always the case when doing it through ketosis. Studies in children using a keto diet to treat epilepsy consistently increase total and LDL-Cholesterol, as well as triglycerides, oxidation and increase particle size.
Keto and diabetes
Can keto reverse diabetes? Yes. I’ve seen it with my own eyes in my patients. Anything that leads to significant weight loss can reverse diabetes, whether it’s a cauliflower diet, cancer or even keto. Weight loss can reverse insulin resistance and improve blood sugar control. The issue is mostly when coming out of ketosis. Studies show that the diabetes returns as soon as the old eating habits come back. Since the adherence of keto diets long term is low, diabetes improvements can be short lived. Even without any associated weight loss, the absence of carbs in the keto diet can also lead to improved blood sugar control. But that doesn’t fix the root cause of diabetes, which is insulin resistance due to fat inside muscle and liver cells (intramyocellular lipids). A good comparison to treating diabetes with keto would be to treat a life-threatening infection with tylenol to simply mask the fever and improve symptoms. When a diabetic on a keto diet hasn’t loss significant weight yet, if they eat any healthy source of carbs, their blood sugar is at high-risk of shooting up. So unless there’s a significant weight loss associated with the keto diet, this diet will simply “mask” the symptoms and high blood sugar temporarily until carbs are reintroduced. Since the number one killer of diabetics is heart disease, and since increased saturated fats in the diet has been shown to increase heart disease and strokes, it could be irresponsible for health care providers to suggest high saturated fat keto diets to diabetics. Although short term studies do show improved metabolic markers, like weight, blood pressure and Hba1C (blood glucose 3 month average), keto diets are also associated with fatty liver, increased insulin resistance, dyslipidemia and systemic inflammation.
Keto and heart disease
Studies done on this particular subject has found increase in all-cause mortality and increases in heart disease rates. In 2016, a US study on low-carb diets by Fung, including 129716 participants with a 20-26 year follow up found that cardiovascular mortality was increased by 14% for those eating a animal-based low carb diet. Those eating a plant-based low carb diet saw their cardiovascular risk decrease by 23%. Even the increases in HDL (good cholesterol) that are sometimes reported with standard keto diets don’t compensate for the increase in LDL (bad cholesterol). Even with significant weight loss that should bring down LDL, some people will have their LDL actually increase, or stay exactly the same, when it should have gone down. Multiple studies also document impaired arterial function (endothelial dysfunction) hours after a low carb, high animal fat meal, meaning that the negative effects on our blood vessels take hours, not years. Not only does the keto diet increase cardiovascular risk, it purposely restricts the types of food most associated with cardiovascular protection. Kind of like a double whammy of kicking you while you‘re down.
Keto and cancer
A typical keto diet is mostly animal foods and we already know that eating red and processed meats are associated with increased risk of cancer. The World Health Organization (WHO) has classified these as class 1 carcinogens, meaning we know for certain that they’re linked to increased cancer risk. It’s logical thinking to assume that over consuming these foods, as typically seen with the keto diet, could pose a significant cancer risk. There are reports out there that keto diets could starve cancer cells that feed on glucose and lead to remission, but it was later found that some cancer cells can feed on ketones too. This hypothesis was initially put forth for brain tumours. Since glucose is the brain’s primary fuel source, and fat doesn’t cross the blood brain barrier very well, it was discovered that brain cells could use ketones as a secondary source of fuel in those fasting. The effect ketones have on brain chemistry for refractory epilepsy treatment was wrongfully extrapolated to brain cancer treatment, but studies didn’t find any measurable benefits on brain tumours. Just like a rumour can spread like wild fire, soon keto-technology companies were selling products to desperate people with anecdotes of keto diets curing cancer. The randomized controlled trials that show the same results? Zero. To date, not a single cancer trial has shown benefits from a keto diet, but many are underway and if some special types of cancers respond to keto diets, I’ll be absolutely thrilled to report to you about it.
Keto and nutrient deficiencies
As typically consumed, the keto diet is rich in animal fats and leads to many vital nutrient deficiencies. Vitamins mostly found in plant foods, like vitamin A, E, folic acid, thiamine and B6 and electrolytes like calcium, magnesium, potassium are widely under consumed on a keto diet. I recently had a patient taking a blood pressure pill called “hydrochlorothiazide”, or a water pill as it’s frequently called. She decide to try keto. Let’s just say the combination of a low potassium diet combined with a potassium lowering pill didn‘t end well. She had dangerously low levels of blood potassium, called hypokalemia, and nearly had a very bad outcome.
But the most important nutrient that‘s deficient on a keto diet is….fiber. Fiber is absolutely necessary to promote growth of beneficial bacteria in our gut microbiome. The absence of fiber leads to quick disturbance of our gut bacteria, and drops in the production of short chain fatty acid (SCFA). These beneficial compounds are the predominant source of energy for our colonocytes, the cells that form our gut lining. This lack of SCFA leads to gut hyperpermeability, or “leaky gut”, as does the increased saturated fat intake. If you’re not familiar with the magical properties of SCFA, go check out the “For Nerds” section of plantbaseddrjules.com or type “microbiome“ in my website’s search bar. The growth of “bad” bacteria leads to over-production of TMAO, a chemical compound linked to inflammation and accelerated atherosclerosis (the narrowing of arteries due to cholesterol deposits). I could go on and on about the benefits of increasing fiber and the risks of not getting enough, but this is detailed right on my website. Fiber only exists in plants, and so the typical keto diet, by definition, is a low fiber diet. Other important nutrients that are deficient include phytochemicals. These are the cancer, inflammation and oxidation fighting chemicals that give blueberries,
tomatoes and broccoli their color and health promoting properties. One study found that to reach the recommended daily intake of most nutrients while eating a keto diet, one would have to consume almost 40000 calories!
Keto in athletes
Keto has been studied in athletes and the findings were disturbing. Since glucose obtained from carbs or protein is the main fuel for muscles, how does an athlete fuel his workouts. Studies in Crossfit athletes doing keto have shown weight loss and significant muscle wasting. The hypothesis would be that the body cannabilizes its own muscle protein in order to obtain a quick source of glucose. Ketosis is associated with calorie deficits, and athletes will resort to consuming protein from muscle in order to obtain proper fuel for their workout. Research has also shown a drop in athletic performance, increased perceived exertion and fatigue in athletes practicing high intensity, short duration sports, all reasons to reconsider a keto diet if you’re a high level athlete.
Other risks to consider
The chronic acidic state caused by keto has also been shown to decrease bone mineralization and increase fractures and kidney stones. While a whole food plant-based diet has been shown to do the opposite of keto on most health parameters. It reverses diabetes, is associated with sustained weight loss, protects against nutrient deficiency, reduces heart disease, cholesterol, blood pressure, constipation and kidney stones, just to name a few.
Plant-based keto
Although there aren’t many well designed vegan or plant-based keto studies, there are low carb versions that we can analyze. Those using mainly low carb plant-based diets are not always deficient enough in carbs to induce ketosis, but the data did show a decrease in mortality when compared to animal-based low carb diets. Are the plants protective or is it the meat that is harmful, or maybe it’s both? Plant-based keto diets would include lots of nuts and seeds, avocados and olives, as well as plant-based oils and butters and non-starchy vegetables like leafy greens. Ketosis is difficult to achieve due to the carb and protein content, so it’s even more difficult to study. But there is anecdotal evidence that those having achieved ketosis while using a plant-based diet have lost significant weight and have had the same short term improvements in metabolic health markers. The long term data is scarce though.
My keto conclusion
Although keto can cause a rapid initial weight loss, this is mostly due to depletion of glycogen stores and water stored in muscles. Once these stores are depleted, then the body enters ketosis. Once in ketosis, appetite is suppressed by ketone bodies, perhaps in a desperate effort to increase survival in times of famine. After the initial water and glycogen depletion, the weight loss mechanism of keto is the same as any other diet, a calorie deficit. But is it worth it? This diet is super difficult to sustain long term, very restrictive and associated with a plethora of documented and well studied risks. Keto proponents will boast about the diet’s magical properties, but until high quality studies back these claims, I will stick to the science already published. I will not recommend keto to my patients, unless breakthrough studies come out convincing me otherwise. If a patient insists on trying a keto diet, I will insist they at least try a plant-based keto filled with low carb green leafy veggies, good fats from nuts, seeds, avocados and olives. The studies on this type of keto are scarce but promising. My main problem with keto is not the promotion of a high saturated fat intake or the absence of fiber, perhaps the most life prolonging nutrient. It‘s the fact that this diet voluntarily restricts the foods most associated with health and longevity: fruits, starchy vegetables and probably the most healthy foods on the planet, legumes such as beans, chickpeas and lentils. If you’re unaware of the “Blue Zones”, check out what these people eat, since they’re the longest living populations on the planet, and trust me, they don’t do keto.
Check out my website plantbaseddrjules.com and look for the “How To” section in the menu. There, you’ll find tips and tricks that helped me on my journey towards a plant-predominant diet. Everything there is completely free, no catches! If you're looking for quick, easy and healthy plant-based recipes, check out plantbaseddrjules.com and download my free recipe eBook!
Look for me on the socials, @plantbased_dr_jules on Instagram and go like my Facebook Page, Plant-based Dr. Jules. If you’re looking for some fitness motivation and are curious to see what a plant-based athlete can accomplish, follow me, @maritimeninja, on my fitness account on Instagram or check out my fitness group on Facebook, called Maritime Ninja Warrior.
Thanks so much for reading!
Plant-Based Dr. Jules 💚🌱
Thanks for reading!
Plant-based Dr Jules 🌱💚
Schwingshackl L, Hoffmann G. Low-carbohydrate diets impair flow-mediated dilatation: evidence from a systematic review and meta-analysis. Br J Nutr. 2013 Sep 14;110(5):969-70. doi: 10.1017/S000711451300216X. Epub 2013 Jul 5. PMID: 23829973.
Vaccarezza MM, Silva WH. Dietary therapy is not the best option for refractory nonsurgical epilepsy. Epilepsia. 2015 Sep;56(9):1330-4. doi: 10.1111/epi.13074. Epub 2015 Jul 22. PMID: 26198854.
O'Neill B, Raggi P. The ketogenic diet: Pros and cons. Atherosclerosis. 2020 Jan;292:119-126. doi: 10.1016/j.atherosclerosis.2019.11.021. Epub 2019 Nov 28. PMID: 31805451.
Groesbeck DK, Bluml RM, Kossoff EH. Long-term use of the ketogenic diet in the treatment of epilepsy. Dev Med Child Neurol. 2006 Dec;48(12):978-81. doi: 10.1017/S0012162206002143. PMID: 17109786.
Brenner DR, Brockton NT, Kotsopoulos J, Cotterchio M, Boucher BA, Courneya KS, Knight JA, Olivotto IA, Quan ML, Friedenreich CM. Breast cancer survival among young women: a review of the role of modifiable lifestyle factors. Cancer Causes Control. 2016 Apr;27(4):459-72. doi: 10.1007/s10552-016-0726-5. Epub 2016 Mar 12. PMID: 26970739; PMCID: PMC4796361.
Phillips SA, Jurva JW, Syed AQ, Syed AQ, Kulinski JP, Pleuss J, Hoffmann RG, Gutterman DD. Benefit of low-fat over low-carbohydrate diet on endothelial health in obesity. Hypertension. 2008 Feb;51(2):376-82. doi: 10.1161/HYPERTENSIONAHA.107.101824. Epub 2008 Jan 14. PMID: 18195164; PMCID: PMC2702133.
Mayer A, Vaupel P, Struss HG, Giese A, Stockinger M, Schmidberger H. Response to commentary by Champ and Klement: Is a ketogenic diet the solution for the hyperglycemia problem in glioblastoma therapy? Strahlenther Onkol. 2015 Mar;191(3):283-4. doi: 10.1007/s00066-014-0793-z. PMID: 25595495.
Hall KD, Chen KY, Guo J, Lam YY, Leibel RL, Mayer LE, Reitman ML, Rosenbaum M, Smith SR, Walsh BT, Ravussin E. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016 Aug;104(2):324-33. doi: 10.3945/ajcn.116.133561. Epub 2016 Jul 6. PMID: 27385608; PMCID: PMC4962163.
Kephart WC, Pledge CD, Roberson PA, Mumford PW, Romero MA, Mobley CB, Martin JS, Young KC, Lowery RP, Wilson JM, Huggins KW, Roberts MD. The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study. Sports (Basel). 2018 Jan 9;6(1):1. doi: 10.3390/sports6010001. PMID: 29910305; PMCID: PMC5969192.
Hall KD, Guo J. Obesity Energetics: Body Weight Regulation and the Effects of Diet Composition. Gastroenterology. 2017 May;152(7):1718-1727.e3. doi: 10.1053/j.gastro.2017.01.052. Epub 2017 Feb 11. PMID: 28193517; PMCID: PMC5568065.
Tremblay F, Krebs M, Dombrowski L, Brehm A, Bernroider E, Roth E, Nowotny P, Waldhäusl W, Marette A, Roden M. Overactivation of S6 kinase 1 as a cause of human insulin resistance during increased amino acid availability. Diabetes. 2005 Sep;54(9):2674-84. doi: 10.2337/diabetes.54.9.2674. PMID: 16123357.
Nicholls SJ, Lundman P, Harmer JA, Cutri B, Griffiths KA, Rye KA, Barter PJ, Celermajer DS. Consumption of saturated fat impairs the anti-inflammatory properties of high-density lipoproteins and endothelial function. J Am Coll Cardiol. 2006 Aug 15;48(4):715-20. doi: 10.1016/j.jacc.2006.04.080. Epub 2006 Jul 24. PMID: 16904539.
