If you’re up to date on the world of health and fitness, then you’ve probably heard of intermittent fasting (IF). And while intermittent fasting is currently one of the hottest dietary trends, it’s hardly a new invention. In fact, the ancient Greek philosopher Pythagoras once praised the virtues of fasting. If you're interested in using an intermittent fasting protocol to enhance your training's effects on your body composition, it's vital that you understand the relationship between intermittent fasting and amino acids—particularly, when you should take amino acid supplements and when you should not.
What Is Intermittent Fasting?
An eating pattern in which participants alternate between periods of eating and not eating, intermittent fasting can have a profound effect on both the body and the brain, enabling participants to lose weight and improve overall health. Unlike other dietary strategies, intermittent fasting doesn’t restrict what foods you eat but instead dictates when you may and may not eat them. As a result, participants often have an easier time adhering to this dietary approach rather than cycling through periods of restrictive eating followed by free-for-alls.
Individuals who utilize intermittent fasting can choose their own schedule for fasting periods and feeding windows. The most popular approach, according to a recent Reader’s Digest article, is the 16:8 schedule in which individuals fast for 16 hours of the day (typically, about half that time is spent sleeping) and fit a day's worth of calories into the remaining 8 hours.
Another common approach is alternate day fasting, in which individuals eat one day and fast or consume very few calories the next.
Others follow a variation of this, the 5:2 approach, in which they fast 2 days a week and eat normally the other 5 days. The approach you choose depends on your personal preferences and lifestyle factors.
Why Intermittent Fasting Can Be More Effective Than Traditional Diets
Intermittent fasting has two significant advantages over traditional diets: first, researchers have found it produces greater fat-burning results as well as accelerated body fat loss even when the daily caloric intake for participants remained the same; second, individuals find it easier to adapt to intermittent fasting and to continue the protocol long term.
It's possible to benefit from intermittent fasting even if you do not change the foods you consume. Findings published in Metabolism showed that participants experienced beneficial changes to body composition and cardiovascular health regardless of which randomized dietary plan they followed.
How Intermittent Fasting Stimulates Enhanced Weight-Loss Results
Numerous studies have shown that adopting an intermittent fasting strategy can help you lose weight and keep it off. And periods of fasting provide health benefits equivalent to those gained by prolonged fasting or caloric restriction.
In the early 2000s, researchers from Yale University School of Medicine and the University of Copenhagen investigated the link between fasting and weight loss. In a series of studies, including this one, they elucidated key mechanisms behind the impressive fat-loss effects of intermittent fasting, namely, increased gene activity, which subsequently increases the total number of calories the body expends as well as the amount of fat utilized for energy.
Research published in the American Journal of Physiology revealed fasting activates genes responsible for encoding proteins and enzymes that increase fat oxidation. In other words, fasting periods activate the body's innate fat-burning systems.
It appears, too, that intermittent fasting can convert white fat cells into brown fat cells, according to a study in the journal Cell Research. While white fat is necessary for storing excess energy and releasing lipids, it’s also associated with obesity and type 2 diabetes. Brown fat, however, burns energy and has other positive effects. Converting white fat to brown—also known as browning—could be a key component in reducing obesity.
Using Intermittent Fasting to Preserve Muscle Mass While Losing Weight
A study conducted at the University of Southern California showed that intermittent fasting spurred weight loss and cut cardiovascular risk factors while keeping muscle mass intact.
Research published in the International Journal of Endocrinology Metabolism echoed these findings, showing that Ramadan fasters lost weight but not protein mass. This makes intermittent fasting an ideal option for athletes and bodybuilders seeking to lose weight while preserving muscle mass.
Psychological Benefits Lead to Improved Adherence
Intermittent fasting can have psychological benefits too. According to a study in Psychosomatic Medicine, diets that rely on calorie counting often trigger cravings and feelings of deprivation in participants. As a result, individuals are more likely to abandon their diets and resume unhealthy eating habits that lead to weight gain.
The study further noted that dieting increases psychological stress and triggers cortisol production.
One of the benefits of intermittent fasting is that it doesn’t require participants to limit what foods they eat, only when they eat them. Plus, the benefits of intermittent fasting—including weight loss—occur regardless of calorie intake.
Further Health Benefits of Intermittent Fasting
Intermittent fasting isn’t just an effective way to lose weight without feeling deprived. Research reveals that fasting periods can also lower your risk of developing a cardiovascular disorder, improve your insulin levels, and even extend your lifespan.
Research shared in the Annual Review of Nutrition found that employing intermittent fasting may influence metabolic regulation thanks to its impact on circadian biology and the gut microbiome, among other factors.
And a study in The American Journal of Clinical Nutrition showed that fasting could improve cardiovascular risk as well as insulin sensitivity. Approximately 610,000 people die of heart disease each year in the U.S., according to the CDC, so intermittent fasting could help save a significant number of lives.
In a broader sense, intermittent fasting may even help patients live longer. A 2017 study done by a team at Harvard University revealed that fasting may manipulate mitochondrial networks inside cells, thereby lengthening lifespans and improving overall health. While doctors don’t yet know how to harness these benefits in a therapeutic sense, the future applications of intermittent fasting appear promising.
Of course, intermittent fasting represents a significant lifestyle change, and not everyone is a good candidate for this dietary strategy. It’s best to speak to a medical professional before beginning any new exercise or nutritional regimen.
Maintaining Healthy Nutrient Intake While Intermittent Fasting
Nutrition during the fast itself is quite simple: do not consume any calories. You can, of course, drink as much water as you desire. Most agree that unsweetened beverages such as black coffee or black and green tea can safely be consumed without adversely impacting your results.
Though it might be tempting to treat yourself to other calorie-free beverages like flavored waters and diet soda, this may not be the wisest choice. Some evidence indicates that artificial sweeteners stimulate an insulin response, thus undermining the creation of a fasted state and its attendant benefits.
While the scientific community continues to analyze exactly how artificial sweeteners impact the health benefits of intermittent fasting, the safest decision would be to avoid consuming them during fasting periods.
What to Prioritize During Feeding Windows
While following an intermittent fasting protocol, you should aim to take in the same amount of calories and hit the same macronutrient totals you would if were eating a standard, nutritionally optimized diet.
While intermittent fasting allows for greater flexibility of food choices than other diet plans, that does not change the basic tenets of good nutrition. Whether or not you're pursuing muscle growth, an optimized protein intake is crucial. You should also be sure to provide your body with a steady supply of healthy fats and complex carbohydrates.
For your first meal after a fasting period, the Yale research team referenced earlier found that choosing a low-carb meal further increases the activity of the genes that result in escalated fat-burning capacity. When participants consumed high-carbohydrate meals, however, the activity of those same genes decreased.
The most serious risk is that you may not take in an adequate number of calories, or may fail to meet the benchmarks for certain nutrient groups. This can compromise your body's muscle-building capacity, especially if you fall short of the ideal protein intake for your size and activity level. As you likely know, protein intake becomes even more important for anyone engaged in strength training.
Intermittent Fasting and Amino Acids
One of the long-term limitations of intermittent fasting is the potential that protein and amino acid intake is reduced below the optimal amount. Many recent lines of evidence indicate that the ideal intake of dietary protein is at least 1.2 grams of high-quality protein per kilogram of body weight per day. For a 100-kg person, this translates to 120 grams of protein a day, or 840 grams of protein each week.
If food is consumed just 5 days per week, and the normal dietary pattern is maintained, then protein intake will only be about 600 grams. To meet the optimal level of protein intake while fasting 2 days out of the week, you’d need to ingest 168 grams of protein on your 5 non-fasting days (or 1.68 g/kg of body weight each day). This is a very high-protein diet.
While achievable, such a high-protein diet is difficult to maintain on a regular basis. And this is where amino acids come into the intermittent fasting picture.
Essential amino acids are the active components of dietary protein and required for muscle protein synthesis. Taking an essential amino acid dietary supplement on days in which food is eaten will ensure that your optimal weekly intake of all essential amino acids are achieved, even if you fast 2 days of the week.
Supplementing with Amino Acids While Fasting
If one of your priorities is to build muscle, you may desire to take in amino acids—specifically, branched-chain amino acids (BCAAs)—while you're fasting. However, doing so will remove your body from the fasted state.
The human body uses 20 amino acids as the building blocks of protein. This includes the nine essential amino acids (leucine, isoleucine, valine, tryptophan, threonine, phenylalanine, methionine, lysine, and histidine), as well as the 11 nonessential amino acids (arginine, serine, cysteine, glycine, proline, alanine, tyrosine, aspartic acid, asparagine, glutamic acid, and glutamine). Consuming even one of these amino acids, let alone multiple, has a similar metabolic effect to the consumption of dietary protein.
One proposed exception to this rule, per the work of some researchers, is pre-workout and post-workout consumption of amino acids when training in a fasted state. Branched-chain amino acids can fuel you through fasted training, serving as a potent source of energy for your muscles.
BCAA supplements vs. EAA supplements
The term branched-chain amino acids refers to the unique, branch-like chemical structures of leucine, isoleucine, and valine. Research has shown that taking between 2 and 4 grams of leucine as part of a complete BCAA supplement can result in desirable health benefits like increased muscle mass, quicker recovery from exercise, and elevated mood and mental focus during endurance exercise.
The three BCAAs are also essential amino acids. When you consume BCAA supplements, their ability to deliver the health benefits you seek will be limited by the quantity of the other EAAs available for muscle protein synthesis and other physiological processes.
Because of this, it's far more effective to ingest BCAAs as part of a balanced EAA supplement. You will only reach the optimal level of BCAA benefits when they're combined with the other six EAAs.