If you aren't fasting more than 24 hours, then you don't have to worry about losing muscle mass. Food is fuel — it's how you power through your workouts and then recover from them. So when you hear about this trend of intermittent fasting for weight loss and other health benefits, you might be suspicious.
You don't need to burn muscle instead of fat, nor will your body automatically burn muscle while fasting. It's possible to lose a bit of muscle mass when you fast, as you also lose water weight and visceral fat. However, it's more likely you'll maintain muscle mass rather than lose or gain it.
No, you typically will not start to lose muscle mass if you don't train for just 1-2 days. Muscle atrophy, or the loss of muscle mass, generally begins to occur after a longer period of inactivity, usually several weeks. Short breaks from training can actually be beneficial for recovery and muscle repair.
Glycogen stores are limited, and liver glycogen is completely depleted after 24–36 h without food10,11. In contrast, muscle glycogen, which is the main substrate during exercise of moderate and high intensity, decreases only by 20–30% after three days of fasting8,12,13.
yes, absolutely. You can fast every day and still workout, when intermittent fasting. There is no negative side effect, in fact you will even receive some growth hormone boosts while fasting to enhance your workout results.
You may also opt for light strength training during a 3-day fast. Spend time outdoors as often as you can and go for walks. Do a few full-body strength training exercises but steer clear of high-intensity interval training (HIIT) and other intense workouts during the fast.
Limited research into intermittent fasting paired with regular resistance training suggests that while someone who is intermittent fasting may lose more weight than someone on a regular diet, their muscle gains and maintenance will be largely identical.
What the research says. A beta-analysis from 2017 looking at five studies on fasted versus fed exercise concluded that working out fasted does not result in greater weight loss or changes in lean muscle mass or fat mass.
"A person who is attempting to lose weight by not eating may lose weight in muscle first before fat," he says. How does that happen? Well, the body likes to go for carbs (glucose) for energy first.
Fasting is a powerful tool for targeting and reducing belly fat. It works by shifting your body's metabolism from burning sugar to burning fat as its primary source of energy. This metabolic shift is what leads to fat loss, particularly in the abdominal area.
Experts recommend 2 to 3 rest days between strength-training workouts like lifting weights. So you can plan resistance workouts that target different muscle groups. For example, you might do upper-body exercises on Monday and lower-body exercises on Tuesday.
Research suggests that resistance training is a powerful way to maintain healthy muscle mass while fasting. Trained males and females who adopted daily TRF for 8 weeks in addition to resistance training had comparable muscle and strength outcomes to individuals who did not restrict their eating window.
However, skipping a workout here and there typically doesn't cause weight gain, and taking regular rest days is healthy for muscle recovery and preventing injury.
Many studies have shown that during fasting, muscle loss doesn't occur, whereas others have. To be safe, ensure a protein-rich meal before bed with carbohydrates, fat and fibre to slow digestion, if you're looking to fast the next day for 24 hours and you're not training. This will ensure no muscle loss occurs.
No, creatine does not break a fast. Creatine contains no calories and does not invoke an insulin response. Keep in mind though, this is only if you consume creatine on its own, such as creatine monohydrate powder dissolved in water, unsweet coffee, or unsweet tea.
The choice between a 48-hour and 72-hour fast depends on individual goals. If the aim is primarily weight loss, both durations can be effective. However, if the focus is on maximizing autophagy, some argue that a longer fasting window, such as 72 hours, may provide additional benefits.
Starvation. When the body is deprived of nourishment for an extended period of time, it goes into “survival mode.” The first priority for survival is to provide enough glucose or fuel for the brain. The second priority is the conservation of amino acids for proteins.
“Strength training is key to building and maintaining muscle. Aim for about 30 minutes of strength-training exercises twice a week,” says Kate. This can include lunges, squats, lifting weights, planks or crunches.
That plan is called the 30-30-30 rule. It's a simple but catchy idea that encourages you to eat 30 grams of protein within 30 minutes of waking up and then get 30 minutes of low-intensity exercise. The 30-30-30 rule now has millions of followers on TikTok.
Fat burning typically begins after approximately 12 hours of fasting and escalates between 16 and 24 hours of fasting.
Doing resistance workouts can help you maintain and build muscle while you're intermittent fasting. Eating enough protein and carbs will help your muscles grow while intermittent fasting. Eating more calories than you burn is helpful (but surprisingly, not essential!) for muscle gain.
We conclude that during short term fasting in obese men: 1) serum FSH concentrations decrease, 2) the pituitary responsiveness of FSH and LRH is blunted, 3) serum testosterone decreases, and 4) the urinary excretion of both LH and FSH increase.
As well as aiding weight loss, not eating for a day can have other health benefits. Research suggests that occasional 24-hour fasting can improve cardiovascular health . Some evidence from research on animals shows that fasting can help fight certain kinds of cancer or even help preserve memory .
That said, the one true way to identify whether or not you're losing muscle is to measure your body composition. The most accurate ways to measure your muscle versus fat involve some pretty fancy techniques (like x-ray scans called DEXAs or underwater weighing), says Oldham Carnes.