I Went Vegan Keto. Here's What Happened to My Body.
An experienced dietitian breaks down the impact of vegan keto on micronutrients, energy levels, and overall well-being.
Published March 6, 2024.
As I start this blog, I’m currently on my sixth day of moderate ketosis. I’m feeling focused and energized—freed from my dependence on coffee. I embarked on a two-week vegan keto journey to see if achieving ketosis was possible following a vegan diet. And I discovered that it is, but not without its challenges. Why would I do this? What are the health implications? Does the keto diet live up to all the hype? Let's find out!
About me: A dietitian on a plant-based keto mission!
As a Registered Dietitian, I am fascinated by how the body reacts to different foods, diets, and lifestyle modifications. I am constantly researching the latest diet trends to evaluate the mechanisms and appeal behind them... and then quickly uncover why they fail to work.
Leveraging cutting-edge technology!
When research is lacking, I turn to cutting-edge technology (like InsideTracker) and my nutrition science background to self-experiment and garner first-hand experience. Here's a walk-through of my latest self-experiment.
The body's energy dynamics
Carbs as a key energy source
On a typical diet, we consume 45-60% of our calories from carbohydrates. Our digestive system breaks down carbs into glucose to fuel the cells in our body. This fuel, or energy, is also known as ‘ATP’. ATP can be formed through distinct, complex processes involving all three macronutrients:
Carbs, however, are most easily and efficiently converted to ATP, making it our body’s preferred energy source of the three.
Low-carb diets and energy adaptation: A vegan keto perspective
With low-carb diets like keto, our body first uses glucose in our blood for energy. As glucose runs low, we break down our supply of stored glucose (glycogen) found in muscles and the liver.
Once depleted of glycogen, the body must adjust to rely on a different energy source—fat. A process known as ketogenesis breaks down fat into ketones—another useful source of ATP.
» Are you on a low-carb diet? Discover key biomarkers you should monitor
Ketosis switches the body to rely on fat for energy
Simply put, ketosis means primarily using fat for energy (fat is preferred over protein as it provides much more energy on a per-gram basis). As ketones increase in the blood, our body releases some of them through urine. Thus, one of the most common ways to measure ketones is with urine keto strips. Reaching a certain threshold of ketones is referred to as ‘being in ketosis.’
How to achieve ketosis through fasting
Achieving ketosis can also occur by fasting—no eating at all! Individuals who fast for extended periods will eventually enter ketosis as well. It can take two days to a few weeks to enter ketosis, depending on your body’s adaptability to burning fat for energy. It took me about four to five days before I noticed ketones in my urine.
Ketosis was first utilized for medical purposes—not weight loss
In the 1920s, scientists discovered that ketosis effectively reduced seizures in children with epilepsy. [1] Interestingly, why and how this works remains unknown. Nevertheless, the keto diet is still prescribed as an anti-seizure treatment, and scientists are even considering it as a potential treatment for other neurological disorders like Alzheimer's and Parkinson’s.
No studies exist in humans yet, but rats on the ketogenic diet exhibit more neuroprotective properties and increased brain energy metabolism. [2-4]
Downsides of a keto diet
While the keto diet does have anti-seizure benefits, it comes with a price. Children placed on the keto diet often suffer from:
- Nutritional deficiencies
- Constipation
- Increased lipid levels (cholesterol and triglycerides)
- Altered gut microbiome. [5-8]
Ketosis for enhanced cognitive vitality!
Ketosis positively affects the brain, as many individuals claim they perceive increased energy and focus in that state—something I also sensed during my experiment.
Ketosis as a dieting tool
The keto diet has since skyrocketed in popularity over the past few years, touted as a way to lose weight—research indicates that ketones circulating in the blood reduce appetite. [9] The macronutrient profile on a keto diet resembles the following:
- 70-80% of calories from fat
- 15-30% calories from protein
- 5% calories from carbohydrates
Optimizing ketosis: Carb intake strategies
Many keto dieters simply aim for less than 50 grams of total carbohydrates or 20 grams of net carbs (total carbs–fiber) as a reliable way to enter ketosis. This often involves limiting nutrient-dense plant-based foods rich in carbohydrates, including fruits, vegetables, legumes, whole grains, nuts, and seeds.
» Learn more about how carbohydrates affect you
Saturated fats and keto
To compensate for the lack of carbohydrates, many keto adopters incorporate more animal proteins into their diet, as they don't contain carbs. What they are rich in, however, is saturated fat. Because of this, many studies show the keto diet directly increases LDL (bad) cholesterol and triglyceride levels in individuals—however, opposing evidence does exist. [15]
Dangers of high protein and low carb diets!
Regardless of these mixed outcomes, a plethora of research shows that long-term adherence to low-carb diets coupled with high protein increases one’s risk of premature death, including death from cancer and heart disease. [16-21] So I had a question: would keto without animal products have better results?
» Check out ten ways to quantify and improve your healthspan
So, I wanted to see how a vegan approach to keto affected my body
People who follow vegan or plant-based diets tend to have a lower risk of chronic disease and healthy body weight. [22-23]
Not a lot of research exists on the combination of vegan keto—which is one of the reasons I tried it myself. I eat a very limited amount of animal products, so this seemed like an interesting experiment, especially with the opportunity to have my blood tested before and after with InsideTracker.
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InsideTracker is a personalized health and wellness platform that aims to help people optimize their biomarkers to live healthier and longer lives. It analyzes genetics, behaviors, and goals to give you personalized nutrition, fitness, sleep, stress, and supplementation recommendations.
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Science-backed recommendations
Comprehensive blood biomarker testing
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My vegan keto experience
I ate less than 20g of net carbs daily during the two weeks. Because of this restriction, I couldn't eat a proper amount of food, including various fruits and vegetables. Which I normally depend on for micronutrients, phytochemicals, and antioxidants that not only have anti-cancer properties but also reduce inflammation and promote longevity.
Surprisingly, I reached the recommended amount of daily fiber (25g), but my typical diet is double this amount. High-fiber diets are associated with a healthy weight and reduced risk of chronic disease. [24]
Sources of protein and fat for a vegan keto diet
For protein, I relied on tofu, lupini beans, protein powder, chia seeds, hemp seeds, flax seeds, select nuts, almond butter, olive oil, avocado, small amounts of edamame, and the occasional Beyond Meat products (burgers and sausage).
I used coconut milk and coconut oil, the only forms of saturated fat in my diet, to make occasional desserts like chocolate pudding and peanut butter cups. Now, let's get into what I experienced!
In my experience, weight loss was just water loss
As previously mentioned, low-carb diets like keto deplete glycogen stores in muscle and liver. Glycogen molecules have multiple water molecules attached like barnacles on a rock (see below), and these water molecules are released when glycogen is burned for energy. Because of this, low-carb dieters lose significant “water weight” during the first days of these diets.
During my two-week experiment, I lost three pounds within the first few days, but then my weight plateaued for the rest of the duration. I certainly attribute water loss to this decline in weight. I should mention that I wasn't trying to lose weight during this experiment.
What I discovered about keto diets and weight loss
Many people insist the keto diet has helped them successfully lose weight. While I don’t doubt this, an important question must be asked—is this due to the keto diet or a change in diet?
The largest contributors to calories in the United States are refined grains, added fats, meats, and added sugars. [14] Most diets, including keto, limit or eliminate at least one of these factors, resulting in some degree of weight loss.
Debunking keto and weight loss myths
People often assume they will quickly lose significant fat from adopting the keto diet, but research does not always support this. In one highly controlled study, individuals were given two diets containing the same amount of calories—a low-fat diet followed by a low-carb one (the keto diet). In this study:
- Subjects lost a little less than a pound on the low-fat, and three and a half pounds on the keto diet.
- However, researchers found body fat loss actually slowed by more than 50% on the keto diet compared to the low-fat diet.
- Instead, the weight lost on the keto diet was due to water and muscle loss! [10]
Vegan keto diet left me less energized during my workouts
That last bullet point is important, and a study examining CrossFit athletes demonstrated similar outcomes. After three months on the keto diet, CrossFitters lost an average of 8% of their leg muscle. [11] The International Society of Sports Nutrition contests that this dieting can impair low and high-intensity workouts. [12]
From my personal experience, I felt weak and fatigued during my workouts, particularly my runs, and my muscle soreness seemed to last longer than normal. In non-athletes like myself, ketosis has been directly related to fatigue during exercise. [13]
» Uncover key nutrients for vegetarians, vegans, and raw vegans
My vegan keto experiment affected my cholesterol levels
Now, what we’ve all been waiting for is how vegan keto affected my bloodwork. My LDL (bad) and HDL (good) cholesterol both improved! Only a handful of studies have examined the effects of low-carb vegan diets on weight and lipid markers. In one study, overweight subjects on a low-carb, vegan diet lost an average of 8-9 pounds and noticed improved LDL and total cholesterol. [25]
Vegan keto diet and LDL cholesterol
Both weight loss and reduced intake of saturated fats help lower LDL cholesterol. I didn’t lose much weight, but I considerably reduced my consumption of saturated fats by eliminating cheese and other dairy products during the keto diet.
Vegan keto diet and HDL cholesterol
As for HDL cholesterol, it is well documented that incorporating more healthy fat (unsaturated) in one’s diet can help to increase this biomarker. [26] Lastly, the increase in triglycerides (fat in the blood) could directly cause the increased fat content in my diet. No other major differences were noted in my bloodwork.
Vegan keto diet: Is it worth it?
- My diet lacked essential micronutrients
- My food choices felt restricted
- I experienced more energy during the day but struggled during my workouts
- I found myself snacking less, but this was not a remarkable change for me—my typically high-fiber diet keeps me satiated throughout the day
- I initially lost a small amount of weight, but it likely wasn't body fat, and my weight plateaued quickly
Much of the research around the keto diet is preliminary and does not support many of the claims made by keto enthusiasts. If you’re willing to put so much work and energy into a diet, why not just focus on adding more nutrient-dense, high-fiber whole foods instead?
For now, I’ll continue to eat my regular, carb-rich diet, limit dairy products, focus on including more healthy fats, and use InsideTracker to continue monitoring my overall health.
References:
[1] https://onlinelibrary.wiley.com/doi/full/10.1111/eci.12591
[2] https://www.ncbi.nlm.nih.gov/pubmed/17284577?dopt=Abstract
[3] https://www.ncbi.nlm.nih.gov/pubmed/18845187?dopt=Abstract
[4] https://www.ncbi.nlm.nih.gov/pubmed/16807920
[9] Gibson AA, Seimon RV, Lee CM, et al. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obes Rev. 2015;16(1):64-76.
[10] Hall KD, Chen KY, Guo J, et al. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016;104(2):324-33.
[11] CF: https://www.ncbi.nlm.nih.gov/pubmed/29910305
[12] Aragon AA, Schoenfeld BJ, Wildman R, et al. International society of sports nutrition position stand: diets and body composition. J Int Soc Sports Nutr. 2017;14:16.
[13] White AM, Johnston CS, Swan PD, Tjonn SL, Sears B. Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study. J Am Diet Assoc. 2007;107(10):1792-6.
[14] Rehkamp S. A Look at Calorie Sources in the American Diet. USDA Economic Research Service. 2016.
[15] https://onlinelibrary.wiley.com/doi/full/10.1111/eci.12591
[16] https://www.ncbi.nlm.nih.gov/pubmed/23372809
[17] https://www.ncbi.nlm.nih.gov/pubmed/23372809
[18] https://www.ncbi.nlm.nih.gov/pubmed/30122560
[19] Lagiou P, Sandin S, Lof M, et al: Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study. BMJ 2012;344:e4026.
[20] Lagiou P, Sandin S, Weiderpass E, et al: Low carbohydrate-high protein diet and mortality in a cohort of Swedish women. J Intern Med 2007;261:366-374.
[21 ]https://www.ncbi.nlm.nih.gov/pubmed/24606898
[22] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073139/
[23] https://www.ncbi.nlm.nih.gov/pubmed/26164391
[24] https://www.sciencedaily.com/releases/2019/01/190110184737.htm
[25] https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/415074
[26] Hodson, L., Skeaff, C., & Chisholm, W. (2001). The effect of replacing dietary saturated fat with polyunsaturated or monounsaturated fat on plasma lipids in free-living young adults. European Journal of Clinical Nutrition,55(10), 908-915. doi:10.1038/sj.ejcn.1601234
