Speak to anyone in the gym today about diet, and you’ll inevitably hear about the Keto, Paleo, and of course, intermittent fasting. Despite its current popularity, fasting is ancient. It’s been practiced in various forms—total abstinence, severe calorie restriction, lengthy, short duration, or intermittently—for religious, health, social, or ritualistic purposes for millennia.
Hippocrates recommended fasting to treat specific illness symptoms. The pre-Columbian peoples of Peru fasted as penance. Buddhist monks fast as part of their meditative practices, and Native Americans fast during vision quests.
Today people still fast for religious reasons, along with cleanse fasts, multiple-day fasts, and intermittent fasts (IF). Although we introduced this subject as part of a diet discussion, intermittent fasting isn’t a diet but an eating pattern. However, it’s an eating pattern that delivers significant health benefits and weight control, and when paired with a healthy diet (or Keto, Paleo, or low-carb), it can produce weight loss.
This article addresses dietary supplementation while fasting in two parts:
- Supplementation during a fasting period
- Supplementation in conjunction with an intermittent fasting program
There is a distinction, but first, let’s explore intermittent fasting to understand the concepts. We’ll dive deep into the world of fasting, its benefits, and (of course) give you our picks for the best supplements to take while fasting. Let’s get started!
Intermittent Fasting – A Pattern of Eating
Unlike multiple-day fasts or detox cleanses, intermittent fasting typically refers to shorter durations, usually twenty-four hours, although there are alternate day intermittent fasts and the 5:2 method (five days of normal eating followed by two days per week of restricted-calorie intake). Each IF method features a fasting or abstinence period, followed by an eating window.
One of the most popular forms is the 16:8, wherein you fast for sixteen hours and then eat normally for eight hours. There’s also a “fast five” fast—nineteen hours of abstinence with a five-hour eating window—and the twelve-hour pattern, twelve hours of fasting, and twelve hours where you can eat. Science tells us a fast must last at least twelve hours for your body to reach a fasted state and trigger the metabolic changes we seek.
For our discussion, we’ll refer to fasting periods and feeding windows—supplements you can take during a fasting period versus those you should avoid, plus a more comprehensive program discussing supplements you may take while practicing IF, which should be taken during your feeding window.
Why differentiate? As you’ll see, certain supplements will either end your fast entirely or kick you out of ketosis if taken during your fasting period. Note: the objective of intermittent fasting is to flip the “metabolic switch.” Fasting helps the body transition from a state of fat storage to one of fatty acid release and oxidation so that you begin burning energy reserves stored in fat for fuel.
Calorie counting or tracking macronutrients aren’t integral to intermittent fasting. The focus is when, not what you eat. Most people naturally consume fewer calories when practicing IF due to fewer meals and less snacking throughout the day. During feeding windows, there are far fewer concerns with supplement types. In fact, we recommend several products that will address potential fasting issues, such as loss of lean mass.
Supplementing During a Fast
Supplementing is crucial while following an intermittent fasting regimen. Done properly, supplements can enhance and accelerate IF’s health effects. The timing of when you take supplements is critical as the wrong supplement at the wrong time may negatively impact the intended metabolic effects.
As a general rule, supplements are acceptable during your fast provided there are no calories, particularly no calories from carbohydrates. We recommend you avoid the following supplements while fasting, at least until your feeding window:
- Protein powder – a perfect lead-in to the topic. Ingesting calories from a protein shake during your fast signals your body the fast is over. Protein triggers an insulin response, and any excess protein converts to glucose. Note: you’ll see protein powder in our recommended fasting stack only during your feeding window.
- We recommend a multivitamin/mineral when fasting—even during the fasting period, provided there are no calories. However, gummy vitamins often contain sugars and should be avoided while fasted.
- Branched-chain amino acids, another part of our IF stack, are more controversial. Some experts suggest sipping low-calorie, sugar-free BCAA while fasting to provide amino acids that prevent muscle breakdown. Others recommend avoiding BCAAs during your fasting period. They contend the amino acid leucine is another supplement that essentially tells your body you’re no longer fasting.
When considering supplements for use while fasting, always review the “Nutrition” or “Supplement Facts” panel. Check the calories and carbohydrates per serving. Avoid supplements using artificial sweeteners or other ingredients that might further lower your blood glucose levels.
Recommended Supplements During Fasting
Intermittent Fasting, particularly when practiced alongside other diet strategies, can create certain nutrient deficiencies. A quality Multivitamin/Mineral delivering the appropriate RDAs of these micronutrients can be excellent nutrient insurance, provided the product doesn’t contain sugars, fillers, or excess calories.
Exogenous Ketones, BHB (Beta-hydroxybutyrate) supplies your body with the fuel it needs and is already using to operate while fasting. Be sure to use a product with no fillers, artificial flavors, etc.
Pre-and probiotics may be consumed while fasted with no adverse effects, as they also contain no calories or carbohydrates.
If taken as a standalone ingredient, creatine is calorie-free and doesn’t trigger an insulin response. Most people, however, source their creatine as part of a pre-or post-workout, which should be consumed during your eating window.
Although exercising while fasting is acceptable, serious strength training is best done during your eating phase, allowing supplementation—pre, intra, or post-workout—to support your efforts.
Electrolytes, potassium, sodium, and calcium may be taken while fasting, again, provided there are no added calories.
Individual micronutrients, such as Vitamin C, D3, and B vitamins.
ZMA (zinc, magnesium, and vitamin B6) is ideal for fasting as other nutrients can interfere with their absorption. Taken before bed or early morning, ZMA fits many IF methods well.
Healthy fats such as Omegas or Fish Oil may be acceptable as they’re typically low in calories and contain no digestible carbohydrates; however, they’re easier for your body to absorb with food, so whenever possible, delay until your feeding time.
Best Supplements To Take While Fasting
Intermittent fasting, dieting, and exercise all contribute to potential caloric and nutritional deficiencies while stressing the body’s muscular and nervous systems. Based on one’s overall health, wellbeing, and physique objectives, supplementation can include an almost endless combination of products.
In this segment, we identify some of the best products for the intermittent faster, for consumption during the eating window. First, most of the products mentioned above to be consumed while fasting can be taken during your eating window—ZMA being the one possible exception. Below are additional supplements that can fit specific needs.
Strength Training
- Protein to achieve your targeted macronutrient requirement and post-workout for repair and recovery. We recommend a blended protein—a combination of whey isolate/concentrate, egg, soy, and micellar casein—for timed absorption and satiety pre-fast.
- Creatine, either creatine monohydrate or HCL, is typically included in your pre, and/or post-workout drink.
- Beta-alanine, for endurance, to buffer lactic acid, a standard pre-workout ingredient.
- Caffeine, for energy and its performance-enhancing benefits.
- BCAAs (Branched-chain amino acids), pre, intra, and potentially post-workout.
- L-Glutamine, for repair, recovery, gut-health, and alleviating DOMS (Delayed Onset Muscle Soreness).
- Nitric Oxide, for vasodilation, either citrulline malate or arginine.
- MCT Oils (Medium Chain Triglycerides)
Endurance Athletes
- Protein – endurance athletes need more protein than the average person, although somewhat less than strength athletes. We suggest a whey isolate to supplement your dietary intake to achieve your 1.2 – 1.4 grams of protein per kilogram of body weight.
- Electrolytes to replace minerals lost during endurance activities.
- Caffeine
- Creatine
- BCAAs
- Beta-Alanine
- Glutamine
For Those Dieting
When practicing IF and dieting, you can easily reduce or eliminate essential nutrients. As such, an MVM (Multivitamin/ Mineral), EFAs (Essential Fatty Acids), and pre-and probiotics should be staples in your supplement regimen. Additional condition-specific supplements for weight loss include:
- Caffeine and Green Tea Extract
- L-Carnitine for burning fat
- L-Tyrosine for mental focus
- Cayenne Pepper Extract
- Synephrine
Fortunately, many popular weight-loss products on the market contain combinations of the above ingredients.
In the weight-loss segment, as in pre-workout products, we recommend products manufactured in a cGMP (certified Good Manufacturing Practices), from brands that feature third-party testing for quality and purity, and certifications such as NSF, USP, or Safe for Sport. Avoid products with proprietary blends that don’t indicate precise dosages of each of these potent ingredients.
In Summary: Supplements While Fasting
When following an intermittent fasting regimen, it’s critical to recognize those foods and supplements which may break your fast and derail progress. If it contains additional calories, carbohydrates, fillers, or artificial sweeteners, beware. When in doubt, defer until your feeding window.
