Intermittent fasting is currently one of the most popular eating patterns. The same is true about veganism, which has risen in popularity by 350% in the last decade (
Each provides their own set of benefits, and you — like many of my plant-based clients — may wonder whether these two ways of eating can be combined.
Intermittent fasting can be successfully done on a vegan diet and may actually provide a variety of health benefits. These range from lower blood sugar and cholesterol levels to a lower risk of cancer and heart disease.
Plus, vegan intermittent fasting may promote weight loss.
However, this diet requires careful planning and is not suitable for everyone.
In this article, I’ll review everything you need to know about vegan intermittent fasting so you can determine whether this way of eating is right for you.
Intermittent fasting (IF) is a way of eating that cycles between periods of eating and periods of fasting.
IF focuses more on when to eat, rather than what to eat. Two of the most common fasting cycles include a daily 16-hour fast or bi-weekly 24-hour fasts.
Vegan intermittent fasting refers to following IF on a vegan diet. So, like all forms of IF, it cycles periods of eating and fasting. However, the foods eaten during the eating cycles will be completely plant-based.
Vegan intermittent fasting requires cycling periods of eating with periods of fasting while following a vegan diet. A person will eat exclusively plant-based foods on this eating pattern.
A vegan diet excludes red meat, poultry, fish, seafood, dairy, eggs, and any foods containing animal-derived ingredients, such as whey, casein, gelatin, or carmine.
Instead of animal-based foods, vegans eat tofu, tempeh, seitan, legumes, nuts, seeds, whole grains, fruits, vegetables, and fortified plant-based foods.
Vegan IF protocols can vary, but most involve splitting either your day or your week into periods of eating and periods of fasting.
During eating periods, you can enjoy an unrestricted amount and variety of plant-based foods. During fasting periods, you should eat little to nothing at all.
The most popular IF protocols include:
- 16/8 method: involves fasting for 16 hours and eating for 8 hours each day. Typically, people on this pattern will skip breakfast and only eat between 12–8 p.m. or 1–9 p.m.
- Eat-stop-eat: involves fasting for 24 hours once to twice per week.
- The 5:2 diet: involves eating 500-600 calories on two nonconsecutive days of the week while eating normally on the remaining 5 days.
Anecdotally, many people consider the 16/8 method the easiest, as most already naturally fast for at least 6–8 hours overnight.
Remember, all foods eaten on this diet must be vegan.
There are many ways to do intermittent fasting. Each involves splitting either the day or week into periods of fasting and periods of eating.
Many studies suggest that IF can result in short-term weight loss. However, it’s unclear whether this weight loss can be easily maintained over time (
People seem to lose about 0.8–13% of their starting weight when following IF for a few weeks to months. It appears that weight loss usually plateaus after 6 months on an intermittent fasting pattern (
Other questions still remain about IF and weight loss. First, it’s hard to tell how much of the weight loss measured in studies is due to the IF pattern versus other factors, such as the quality of the diets that participants ate (
Plus, many studies used small sample sizes or ran for short periods of time, while some didn’t report on whether people following the IF diets experienced any side effects (
That means there are still a lot of unknowns when it comes to whether IF — including vegan IF — is safe and effective for significant, sustainable weight loss.
Intermittent fasting on a vegan diet comes with both potential benefits and risks, but we need more research into the effects of this diet.
Possible health benefits of vegan intermittent fasting
Both animal and human studies suggest that intermittent fasting can result in a few health benefits, including:
- Heart health: Intermittent fasting may slightly reduce triglyceride and low density lipoprotein (LDL or “bad”) cholesterol levels, as well as lower the risk of heart disease (
3, 7, 8).
- Blood sugar and insulin sensitivity: Human studies suggest that IF may reduce blood sugar levels and increase the body’s ability to recognize and utilize insulin (
- Menstrual cycles: IF may help people with polycystic ovarian syndrome experience more regular menstrual cycles (
- Longevity: Many animal and a few human studies suggest that IF may help you live longer. However, more research in humans is needed before strong conclusions can be made (
- Brain function: A few animal and human studies suggest that IF may offer some protection against Alzheimer’s disease and reduce symptoms of epilepsy. However, more research is needed (
- Reduced inflammation: Animal studies suggest that IF may reduce inflammation. However, human studies are needed to confirm this (
- Cancer risk: Some animal and a few human studies suggest that IF may prevent DNA damage and help kill damaged, pre-cancerous, and cancerous cells. However, more human studies are needed (
Vegan diets have been linked to many health benefits, including (12,
- lower blood sugar levels
- lower risk of cancer
- lower blood cholesterol levels
- lower triglyceride levels
- up to a 25% lower risk of dying from heart disease
In addition, a vegan diet appears to provide relief from pain caused by arthritis (
It’s possible that combining a vegan diet with an IF protocol may provide a mix of some or all of these health benefits.
That said, no studies currently exist on vegan intermittent fasting. Therefore, more research is needed before strong conclusions can be made.
Potential risks of vegan intermittent fasting
IF can make it more challenging for you to meet your nutrient needs — and arguably even more so on a vegan diet.
That’s because IF requires you to meet your daily nutrient needs within a shorter period of time, likely while eating a smaller overall number of meals and snacks.
A vegan diet is naturally lower in some nutrients like vitamin B12, iodine, iron, calcium, zinc, selenium, and long-chain omega-3s. Eating a larger volume and variety of foods is often required to meet your nutrient needs as a vegan (
That can be difficult to achieve when you limit yourself to eating only within a certain window of time. It requires careful planning and a certain level of nutrition knowledge.
If you’re new to a vegan diet or interested in trying a vegan intermittent fasting protocol, I strongly encourage you to seek guidance from a registered dietitian (RD) to help make sure your diet is well-balanced.
In addition to diet quality, long periods of fasting may lead some people to binge when breaking their fast.
Binge eating disorder (BED) involves eating larger than normal amounts of food in a small period of time, with a feeling that you don’t have control over your eating (
If you notice that your vegan intermittent fasting diet promotes BED-like behaviors, it’s likely not the right eating pattern for you.
Some research further suggests that some women’s hormones may react differently to intermittent fasting than men’s. Anecdotally, some women report losing their periods during IF (
Few studies exist on the topic, so until more is known, people who want to try IF should start off gradually. Stop immediately if you notice any menstrual irregularities, including a lack of menstruation.
Who shouldn’t try vegan intermittent fasting?
Vegan IF is not recommended for children or anyone who is pregnant or breastfeeding (
It’s also unsuitable for people living with thyroid abnormalities, who have a history of eating disorders, or who take insulin or blood sugar-lowering medicines (
Vegan intermittent fasting may reduce your risk of certain diseases. However, it requires careful planning and is not suited for everyone, especially people who are pregnant or breastfeeding, who have a history of disordered eating, or who take certain medications.
A well-planned vegan diet typically requires supplements and fortified foods in order to meet your nutrient needs.
A vitamin B12 supplement is the bare minimum. Depending on where you live, your food preferences, and your meal-planning skills, you may also need vitamin D, iodine, iron, calcium, zinc, selenium and omega-3 supplements (
If you’re interested in giving vegan intermittent fasting a try, start by choosing which IF protocol is most realistic for you based on your life, work, and leisure habits.
Then, start slowly; perhaps by starting with a 12-hour fasting window rather than a 16-hour one, or 1 calorie-restricted day per week rather than 2.
Remember that you’ll have access to a restricted amount of meals and snacks each day or week to meet your nutrient needs. It’s likely best to plan your meals and snacks ahead of time, to help ensure they are as nutrient-rich as possible.
To further boost the nutrient content of your diet, opt for whole and minimally-processed plant foods whenever possible, and try limiting most processed or ultra-processed foods.
Finally, have a review date in mind. If you feel terrible, or haven’t gotten any of the results you wished for by the time your review date rolls around, vegan intermittent fasting may not be the right eating pattern for you.
Including plant-based supplements, starting slow, planning your meals and snacks ahead of time, and having a review date in mind can help make your vegan intermittent fasting experience more successful.
Your vegan intermittent fasting meal plan will vary according to which IF protocol you choose to follow and what foods you like and have access to. This means there is no one universal meal plan for everyone.
However, the following guidelines remain true regardless of whether you opt for the 16/8, eat-stop-eat, or 5:2 protocol, and should help you a balanced vegan IF meal plan of your own (
- Well-balanced meals and snacks: Ensure that most of your meals and snacks include some tofu, tempeh, beans, lentils, or peas together with whole grains and a variety of fruits or vegetables.
- Leafy and green vegetables: Plan to have at a minimum of 2–3 servings of leafy greens each day. These include lettuce, arugula, spinach, kale, cabbage, broccoli, collard greens, and Swiss chard, to name a few.
- Brazil nuts: Include 1–2 Brazil nuts each day to help you more easily meet your selenium needs.
- Flax, hemp, or chia seeds: Include 1–3 tablespoons (15–45 mL) of ground flax, hemp, or chia seeds per day, to increase your intake of omega-3s.
- Other nuts and seeds: Plan to eat an additional 1–2 ounces (28–56 grams) of other nuts or seeds each day.
- Fortified foods: Make sure to include at least 2–3 servings of a fortified plant milk or yogurt each day to more easily meet your calcium-needs.
Your meal plan should be mostly based around whole or minimally-processed foods, as these will help you best meet your daily nutrient needs.
However, try keeping some room to enjoy a few processed foods, sweets, or baked goods from time to time to minimize the risk of BED and avoid falling into an overly restrictive eating pattern.
Keeping the guidelines above in mind when meal planning for your vegan intermittent fasting diet will help ensure you more easily meet your daily nutrient needs.
Vegan intermittent fasting involves following a vegan diet on an intermittent fasting protocol.
Individually, both ways of eating have been linked to various health benefits. These may include lower blood sugar and cholesterol levels, a lower risk of cancer and heart disease, and even a longer life.
The combination of the two eating patterns may be expected to provide a mix of some or all of these benefits. However, more research is needed to confirm this.
Keep in mind that both ways of eating are, in themselves, restrictive in nature. Therefore, vegan IF can make it more challenging to meet your nutrient requirements than either diet on its own.
If you’re interested in giving vegan intermittent fasting a try, consider seeking guidance from an RD to ensure that your diet remains well-balanced.