In this article:

  • What is Alternate Day Fasting?
  • Benefits of Alternate Day Fasting
  • Is Alternate Day Fasting Right for YOU?
  • Pitfalls of Alternate Day Fasting
  • Should You Workout on Days of Alternate Fasts?
  • Sample Schedule 

What is Alternate Day Fasting?

Alternate Day Fasting is a variation of intermittent fasting that allows you to eat what you want one day followed by a pretty significant caloric drop the following day – as much as cutting your caloric intake down to just 20 – 25% of your basal metabolic rate or active metabolic rate. 

It’s not so much a change in WHAT you eat as it is a change in the pattern of eating. You’re not focused on ratios of macros (how many carbs, fat or protein) so much as dropping your caloric intake strategically.

If you don’t know what your basal metabolic rate or active metabolic rate is, there are many calculators you can use or you can stick with a 500 calorie a day intake on your alternate fasts days to make it easy.

You can also track your weekly caloric intake using a tracker like cronometer or my fitness pal and then take the daily average and reduce by 20-25% for your alternate day fasts.

But why would use alternate day fasting?  You could certainly just reduce calories a bit each day, or do intermittent fasting daily.  So let’s look at the benefits of alternate day fasting…

Benefits of Alternate Day Fasting

Stop Tracking Carbs, Fat and Protein

One of the reasons diets don’t work is because of the constant state of deprivation for weeks and months on end.  Alternate day fasting works whether you are following a paleo, vegan, vegetarian, or keto type diet because the focus is on caloric intake, not the composition of the calories.

Lowered Cholesterol

Decreased in total cholesterol occurred in study participants and LDL cholesterol- both decreased help lower the risk for heart attack and stroke.

Heart Health

Participants in a study in the American Hournal of Clinical Nutrition had a slower heart rate and a sronger heart.


Autophagy is a process cells use to clean up damaged cells that aren’t working optimally. How autophagy contributes to diseases is only beginning to be understood; however, there are clues that it plays a role in inflammation, cancer and neurodegeneration. Low levels occur all the time, but autophagy increases when you’re fasting or working out.

Helps Preserve Lean Muscle Mass

Alternate day fasting is not a true fast at 500 calories – it’s more of a modified fast.  The 25% intake  is just enought to prevent the loss of muscle mass, which is super important long term for overall health and weight maintenance.  Most diets have about a 75% fat/25% muscle loss ratio – the alternate day fats flips the swtich with about a 99% fat/1% muscle loss.

Is Alternate Day Fasting Right for YOU?

If you’re someone that doesn’t enjoy restricting carbs, proteins, or fats or excessively constantly counting calories, alternate day fasting might be a good option for you.

But alternate day fasts aren’t right for everyone. It’s important to know that if you have any of the following conditions, then ADF might be too much: underweight; struggling with weight gain (for adults); 18 years old and younger than pregnant or breastfeeding age group individuals should avoid intermittent fasts since they need sufficient calories on a daily basis during development stages in order fuel their body properly.

Pitfalls Of Alternate Day Fasting

While alternate day fasts can certainly be beneficial, there are some definite drawbacks.

1.  Watch for changes in hunger.  Most people ‘s hunger levels stabilize rather quickly, but keep an eye out for continued hunger on alternate day fasts.  You might also run into trouble if you’re NOT in a state of ketosis but are using high levels of fat on fast days. Because fat is so calorically dense, if you’re on a very low carb, high fat diet 3-500 calories a day isnt going to fill you up.  

2. Missed Opportunities for focusing on nutrient dense, low glycemic meals consistently.  Alternate day fasting is focused on changing the caloric intake and the timing of calories.  But there are some real missed opportunities to focus on controlling blood glucose levels and nutrient density that can pay dividends over the long term.  So while ADF can be beneficial in the short term, consider other alternatives for a long term approach.

3. Hormone Flux.  Keep an eye on important signals your body sends regularly – hunger, energy, cravings, sleep, and mood.  For some people, fasting days can produce higher levels of cortisol if they drop into a lower blood sugar based state and can ultimately impact thyroid.

4.  Watch For Binge Eating.  While not common, keeping an eye out of bingeing the day after an alternate day fast.  Focusing on regulating blood sugar, nutrient dense meals and staying hydrated can really offset this tendency.  

7.  Workouts can suffer with the drops in caloric intake. Definitely pay attention to the intensity of the workouts youre trying to engage in and how your body responds.  This may just not be the time to kick up your HIIT training.  Walks, weightlifting, yoga, dancing and other forms of exercise might make a difference if you expereince spikes in cravings or extreme fatigue.


Should You Work Out On Alternate Fast Days?

Physical activity doesn’t need to be limited, even on your fast day.  You can continue to maintain your 10k steps a day and your detox workouts. In fact, one on study, participants who engaged in alternate day fasts and exercised had more muscle, increased belly fat, lowered cholesterol. 

If you structure your workouts on your fasting days, consider exercising before your meal.

alternate day fast workouts

What Does 500 Calories Look Like?

These are sample recipes from The Every Other Day Diet, by  Krista Varady PhD.  Her book is a great resource on every other day dieting, or alternate fasting and provides practical 500 calorie meals and snacks and even options for eating out.

turkey avocado

Turkey & Acocado Sandwich

1 Arnold Sandwich Thins Roll

1 Laughing Cow Light Queso Fresco & Chipotle Cheese Wedge

4 Ounces thinly sliced deli turkey breast

2-3 Tomato slices

1/5 pitted and peeled avocado, thinkly sliced

alternate day fast bbq chicken

BBQ Chicken & Broccoli Wrap

3 ounces rotisserie chicken breast shredded

1/3 cup corn

1/2 cup broccoli slaw

2 teaspoons jarred bbq sauce

1 Tbsp fat free ranch dressing

1 multigrain Flatout Soft 100% Whole Wheat Flatbread

black bean corn salad

Black Bean Corn Salad

3/4 cup rinsed and drained canned black beans

2/3 cup corn

1 cup chopped sweet pepper

1 small tomato, chopped

1/2 samll peeled and pitted avacado, chopped

1 Tbsp. red wine vinegar

1/4 teaspoon ground cumin

Tips For Success:


1.  Weigh Daily.  Self weighing is actually linked to better maintenance and loss, and average fewer calories a day when weighing daily – as much as 347 fewer. 

2. Focus on Lunch and Dinner.  On your alternate fast days you might benefit from eating your 500 calories at lunch and dinner, not breakfast.  Consuming your calories too early in the day can leave you pretty empty by dinnertime and your regular day.

3.  Plan Ahead.  While alternate fast days offer a lot of flexibility, you’ll need to plan ahead for the 500 calorie days so tat you stay on track.

4.  Avoid 500 Calories Worth of Snacks. Even though it might be tempting to spread the 500 calories out throughout the day in the form of snacks, you’ll likely consume mroe than the 500 calories AND not feel satisfied.

5.  Stay Hydrated. Water certainly has the power to reduce appetite and  boost caloric burn (19).  Water stimulates the sympathetic nervouse system, increasing metabolic rate by as much as 24% for an hour after drinking half a liter of waer.

Books We Recommend For Further Reading

The Alternate-Day Diet Revised: The Original Up-Day, Down-Day Eating Plan to Turn on Your "Skinny Gene," Shed the Pounds, and Live a Longer and Healthier Life Paperback – Illustrated, December 31, 2013
The Rain Barrel Effect: How a 6,000 Year Old Answer Holds the Secret to Finally Getting Well, Losing Weight & Feeling Alive Again! Paperback – March 24, 2018
Intuitive Fasting: The Flexible Four-Week Intermittent Fasting Plan to Recharge Your Metabolism and Renew Your Health (Goop Press) Kindle Edition