There’s no shortage of info on the purported benefits of intermittent fasting (IF), but that doesn’t guarantee this popular health hack will work for you.
IF seems to work great for those who aren’t breakfast people, but it might not be ideal for exercisers who rely on healthy carbs and protein to fuel their performance. Below, we break down the pros and cons of intermittent fasting for your fitness goals, so you can plan out whether IF is right for you.
Pros of Intermittent Fasting for Fitness
- It can help you avoid digestion issues
For people who often deal with digestion issues during a workout, intermittent fasting can offer relief when they train on an empty stomach. When the body isn’t actively digesting food, there’s less risk of bloating, cramping, or discomfort that’s triggered after eating in people with sensitive stomachs or GI issues. In other words, fasting before workouts can help the body focus on performance rather than digestion, making it easier to finish your workout without feeling like you might need a restroom break.
- You might lose fat
With fewer meals to plan and prepare, intermittent fasting can simplify meal planning and reduce the temptation to snack mindlessly. From a practical standpoint, that might seem like a solid way to nix extra calories from your day. But even deeper than that, some research suggests IF might encourage the body to tap into stored energy — particularly, fat stores — to help you lose more fat, according to the American Diabetes Association (ADA).
The verdict is still out on whether IF will actually help you lose more body fat in the long run. At the end of the day, fat loss is more dependent on the total calories you eat in a day—and a calorie deficit, whether it’s through diet or exercise, or both, is the most research-backed way to lose weight.
- You might enjoy better insulin sensitivity
Regular fasting periods can improve insulin sensitivity in people with blood sugar issues, per a 2022 study. Stable blood sugar levels can help support muscle recovery and fat loss.
Also good to know: Exercise actually helps lower blood glucose levels and increase insulin sensitivity, according to the ADA. Insulin helps move the glucose in your bloodstream into your cells to use for energy; but when your muscles contract during exercise, your cells are able to use glucose for energy whether or not insulin is available.
Cons of Intermittent Fasting for Fitness
- Your energy levels may take a hit
Fasting can sometimes lead to fatigue or low energy, particularly during high-intensity or strength training sessions. Energy, in the form of calories, comes from food. Specifically, carbs give you the fuel you need because they turn into glucose, your body’s preferred source of energy. When you don’t have food in your system, you have less energy, which can show up as slower, more fatigued workouts. That means you might not be able to hit a new PR or even feel like you got an effective workout in.
What’s more, working out on an empty stomach may lead to dizziness, headaches, and muscle cramps — and that’s especially true if you’re dehydrated, per the Cleveland Clinic. If you do decide to do a fasted workout, make sure to drink plenty of fluids to avoid the side effects of dehydration.
- You might be low on certain nutrients needed for recovery
Eating within limited time windows may reduce overall nutrient intake, which can affect the way your muscles recover and rebuild.
If your goal is to gain more muscle, you’ll want to have some protein before or after a workout. Within an hour after your workout, your muscles store carbs and protein as energy to help kickstart the recovery process, according to the ADA. But if your body doesn’t have the carbs and protein it needs, that might impair recovery.
- It’s difficult to sustain
Intermittent fasting can be hard to stick to long-term. For some, it may lead to overeating or poor food choices during feeding windows.
If you have health goals like losing body fat, eating those extra calories you probably wouldn’t have consumed if you didn’t fast may make or break your results. To make intermittent fasting easier to stick to, you can gradually ease into the practice and choose fasting windows that align with your lifestyle. You’ll also want to focus on balanced meals that satisfy hunger and provide all the nutrients you need.
Final thoughts
Intermittent fasting may help you avoid digestion issues during a workout and can increase your insulin sensitivity; and although not fully conclusive, some research suggests IF might also help you lose body fat. However, intermittent fasting may not be the best choice for people who are generally low on energy or those on a muscle-building diet who need the extra protein. If you’re looking into IF, start with a more realistic fasting approach, like fasting for 12 or 14 hours overnight and see how you feel.
About April Benshosan
April is a writer, editor, and content strategist with a Master’s degree in Publishing. Her work highlights her passion for responsible health journalism, and she’s been published in print and digital outlets, including Women’s Health, EatingWell, SHAPE, Well+Good, LIVESTRONG.com, Health.com, Abbott, and more.
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