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Is prolonged and intermittent fasting safe?

Is Prolonged and Intermittent Fasting Safe?

A doctor named Alan Goldhamer supervises patients through therapeutic fasting that lasts between 5 and 40 days. has reported ZERO deaths from water fasting, after having over 10,000 fasting patients. So, even though numerous adverse side effects can occur with water fasting, the mortality rate is extremely low (1). While I don’t recommend dry fasting or prolonged fasting without doctor supervision, it is highly possible that you could fast for many weeks without it being life-threatening. Prolonged fasts typically end much sooner than planned due to the psychological difficulty of going without food (2) in addition to the physical challenges of feeling hungry and unwell.

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How long should you fast?

During autophagy, the human body is quite literally detoxifying. That said, it is best to listen to your body and break the fast if you start to feel sick. Fasting has significant psychological effects, like the keto diet due to our bodies need for carbohydrates (2). In some cases, people fast for several days or weeks, then safely return to good health upon breaking the fast with mostly water and health foods. In other cases, fasting for long periods of time can have detrimental effects on people’s health. While some studies have shown that multiple-day fasts are beneficial to human health, more research should be done on best practices.

Most people view starvation as an entirely bad thing – even if it means skipping only one meal – thinking it’s just another type of calorie restriction with short term results. While this can be true for fasting, the negative effects of starvation are more likely to occur when you put yourself on a very low-calorie diet (VLCD). One study determined that after 10 weeks of undereating (due to VLCD without fasting), your hormones change and cause you to feel extra hungry for the next year or longer, leading to weight gain in the long run (3).

water-fasting-dry-fasting-health-benefits

Some people develop a liking for fasting, and practice it regularly.

A 24-hour fast every couple weeks or a daily 16-hour intermittent fast is generally safe for healthy individuals. Intermittent fasting has gained popularity in recent years and has been proven effective for fat loss in many studies (4). Many people find that it feels completely normal to go without food from dinner until the following day at lunch time, which is why the 16-hour fast is usually a good starting point. Some people start with 12 hours, then slowly build up over time to achieve 16-24 hour fasts through practice. Many fasters go beyond the 24 hour mark for days or even weeks to reap the health benefits. However, with the risks associated with prolonged fasting I do not personally recommend it. In fact, a 2017 study shows that intermittent fasting has all the same benefits as prolonged fasting such as weight loss, improved liver function, and glucose homeostasis (5).

When intermittent fasting, choosing a vegan version of the ketogenic diet during your eating window is much less harmful to our bodies than the animal-based version. Low-carb plant-based foods may reduce risk of heart disease as opposed to increasing the risk (like meat does) (6). However, it is not required to eat low-carb foods to reap the benefits of ketosis when fasting. Regardless of what diet you follow, make sure you are getting enough calories, proteins, vitamins, and minerals. If you have an eating disorder, nutrient deficiency, or Type II Diabetes, you should not attempt fasting. Hire a vegan dietitian, nutritionist, or nutrition coach to help prepare a healthy and safe plan for you. As always, talk to a medical professional before making any diet changes and to discuss any health risks associated with fasting.

Written by Kelly Gibson, Owner at Kelly Athletics LLC. Kelly is a Personal Trainer and Holistic Nutritionist in Pittsburgh Pennsylvania. She is passionate about being a vegan coach, and loves to help women transition to a plant-strong diet.

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References:

  1. Gustafson, Craig. “Alan Goldhamer, dc: Water Fasting—The Clinical Effectiveness of Rebooting Your Body.” Journal of Integr Med (Encinitas). Vol 13(3): 52–57. Published June 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684131/. Accessed Aug 3, 2018.
  2. Mehrpour, Maryam et al. “Autophagy in health and disease: 1. Regulation and significance of autophagy: an overview.” American Physiological Society, vol 298, issue 4. Published April 2010. https://www.physiology.org/doi/10.1152/ajpcell.00507.2009. Accessed August 1, 2018.
  3. David Baker and Natacha Keramidas. “The psychology of hunger.” American Psychological Association. Published October 2013, vol 44, No. 9. http://www.apa.org/monitor/2013/10/hunger.aspx Accessed July 29, 2018.
  4. Kollias, Helen. “Weight Loss & Hunger Hormones: Why ‘willpower’ may not be your problem.” https://www.precisionnutrition.com/fast-weight-loss-changes-hunger-hormones. Accessed July 31, 2018.
  5. Moro, Tatiana et al. “Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males.” J Transl Med. Published 2016. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064803/ Accessed July 24, 2018.
  6. Kyoung-Han Kim & Yun Hye Kim. “Intermittent fasting promotes adipose thermogenesis and metabolic homeostasis via VEGF-mediated alternative activation of macrophage.” Cell Research Journal. Published Oct 17 2017. https://www.nature.com/articles/cr2017126.  Accessed July 31, 2018
  7. DJ, Jenkins et al. “Effect of a 6-month vegan low-carbohydrate (‘Eco-Atkins’) diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: a randomised controlled trial.” BMJ Journals. Published Feb 5 2014. https://www.ncbi.nlm.nih.gov/pubmed/24500611 Accessed July 25, 2018.
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Is Vegan Keto the Best Ketogenic Diet?

Is Vegan Keto the Best Ketogenic Diet?

Vegan vs Keto debate: Are they compatible or too different?

Are plants superior to meat? As mentioned in my previous article, the ketogenic diet has some good, bad, and ugly qualities. Superfoods like kale are especially valuable to a typical ketogenic diet. Majority of superfoods are ingredients from plants, so why not eat a fully plant-based diet? For example, kelp contains more than 5X as much iodine than any fish of a sea animal (1), and brazil nuts contain more selenium than any meat of a land animal (2).

vegan-keto-tofu-leafy-greens

Does it fit my macros? Plant-based foods have a variety of macronutrient profiles, ranging from low carb to high carb and low fat to high fat. So, if you are concerned about the high intake of cholesterol but still want to get the benefits of a keto diet, you can follow a low-carb vegan keto diet which consists of soy, oils, vegan cheese, nuts, some veggies, and minimal fruit. Plant-based foods are entirely devoid of cholesterol, and usually low in saturated fats. The reason I highly recommend a cholesterol-free diet is because the tissues of our liver and small intestine produce cholesterol all on its own, with or without dietary cholesterol (Berardi 89). In fact, dietary fiber can lower blood cholesterol levels (Berardi 53), so by following a higher-fiber plant-based diet you can maintain a low cholesterol level.

So is vegan keto high fiber? Many vegetables recommended on the keto diet are high in fiber, however the bulk of a vegan keto diet is still somewhat lower in fiber due to its high fat content. Even though tofu and oil are derived from plants, they aren’t foods that should be consumed in excess.

Tofu has a small amount of fiber (4-5g per block) which is definitely more than the zero grams of fiber you get from meat, dairy, fish, and poultry (yep – animal products are completely void of fiber!). Processed cheeses like daiya and plant-based meats like the Beyond Burger are cholesterol-free which is a bonus but they do have less fiber than their whole food unprocessed counterparts. Oil – on the other hand – is another completely fiber-less food which can damage our endothelium, increase inflammation, and contribute to atherosclerosis (4). It is unlikely to achieve keto’s fat standards without having some oil. You can supplement with psyllium husk for fiber, but again, it is not recommended to replace food with supplements.

Will I be missing anything? If you do still want to go keto, you can download a free vegan keto shopping list here.  At first glance you may think I’m making false claims because there’s a lot of fruit and veggies on the keto shopping list. However, keep in mind that only 5-10% of your calories can come from these foods, and since majority of plant-based foods are high in carbohydrates, you will be stuck eating the same low-carb foods over and over and over again. Since many leafy vegetables are low-calorie, you can get away with having a higher amount of them, but sweet fruit and veggies are nearly untouchable. So again – your diet will be mostly tofu, processed dairy and meat alternatives, oils, nuts, and some green veggies – meaning you are at a similar risk of vitamin A and vitamin C deficiency as a meat-based keto diet. It is unlikely that you could maintain this much restriction for a lifetime but if you want to take the challenge – go for it, but plan carefully!

low-carb-vegan-food-ketogenic-diet

Do I need to track calories? Some sources will say that counting calories is not required on the keto diet, but if you don’t then you could easily overeat. On a keto diet (vegan or not), you would need to get used to eating smaller portions of food, because fats are more than twice as dense in calories as carbs or proteins and in many cases lack water content. So if you normally eat 2 cups of strawberries per 100 calories, now you will eat only ½ cup of tofu per 100 calories and less than 1 tablespoon of oil per 100 calories. The good news is, you can still eat a lot of green vegetables like 3 cups of broccoli or 20 cups of lettuce per 100 calories. If you can manage to pull off a monster salad like that, then you are the King of Keto! If you’re ready to take on this diet and all its’ restrictions, then ketosis may help you with fat loss – maybe. If you want a truly incredible experience, there is a better method of getting into ketosis without any diet at all – which I will cover in the next page.

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Resources:

  1. The World’s Healthiest Foods. The George Mateljan Foundation, Inc. “iodine.” http://www.whfoods.com/genpage.php?tname=nutrient&dbid=69. Accessed July 20, 2018.
  2. Dr Axe. “Brazil Nuts: The Top Selenium Food that Fights Inflammation.” https://draxe.com/brazil-nuts/. Accessed July 20, 2018.
  3. Berardi, John et al. Precision Nutrition: The Essentials of Sport and Exercise Nutrition, Second Edition. Precision Nutrition, Inc., 2012.
  4. Oliveira, Rosane. “Why You Should Opt Out of Olive Oil.” UC Davis: Integrative Medicine. Published May 11 2016. https://ucdintegrativemedicine.com/2016/05/why-you-should-opt-out-of-olive-oil/#gs.0cf3OOk. Accessed July 19, 2018.

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