Did your mom ever tell you it was dangerous to swim after you eat? Apparently, those cake, burger, and fries would drain blood from your muscles and instead hold it in your digestive system, causing excruciating cramps that are so terrible you could drown.
Is this advice valid or is it more of a myth? Is Exercise After Eating Good Or Bad For You? Even if you look at the research, it’s a hotly debated question that doesn’t have a straightforward answer.
So what’s the deal? As you exercise, remember that there is a huge difference between a gentle walk and a triathlon. When it comes to eating, too, there is a strong contrast between a muesli bar and a three-course menu.
We researched whether it is safe to exercise after eating.
It’s not that easy
There is no one-stop answer, as both eating and exercise occur along a spectrum.
First, consider the time frame. Are we talking about exercise right after a meal? An hour after eating? Or longer?
Then there’s the fact that snacking on an apple and cramming at Thanksgiving dinner are two sides of the same coin. A leisurely stroll through the park and a triathlon are also considered sporting activities.
In short, there are several variables at work here.
Diet and exercise, along with genetics, the environment and lifestyle, make significant contributions to your health. But the relationship between the two is a bit complex.
You need nutritious foods to keep your activity going and to repair your tissues after exercise. On the other hand, the way your body moves can affect your digestion by stimulating your bowels and increasing bowel activity.
The question of whether post-meal exercise is a good idea cannot be answered unequivocally, as it depends on your goals. Maybe you are trying to lose body fat, or maybe you are an athlete who relies on food for fuel.
It could make you sick
Some people feel sick and sluggish when they exercise right after a meal. Exercise-related vomiting is real, friends.
So if you don’t want to throw up on the weight bench, soccer field, or tennis court, wait a while between eating and doing physical activity.
Higher blood sugar could help super athletes … but fasting sports could burn more fat
For some, exercising after you eat is a great idea.
It’s probably no surprise that if you eat before exercising, your blood sugar will be higher. A 2018 review compared sober and fed workouts and found that people who ate before exercising had elevated blood sugar, which might be ideal for serious athletes.
Sports fasting increased the amount of circulating free fatty acids (FFAs) after exercise, which result from the breakdown of fat cells. In other words, when you exercise on an empty stomach, you burn more body fat.
If your goal is to lose body fat, you may think that the best plan is not to eat anything before exercising. But keep your horses – it’s not that straightforward.
While some studies suggest that fasting exercise has potential benefits, there’s no concrete evidence that it helps with fat loss.
In a small study from 2013, the researchers divided 16 women into two groups in the obese BMI category. Both groups participated in 18 high-intensity interval training sessions over 6 weeks, but one group trained on an empty stomach and the other trained on an empty stomach.
The researchers found no significant differences in body composition, muscle oxidative capacity, and blood sugar control between the two groups.
Carb loading * could * increase performance with prolonged training
And what about the performance? That too should be considered.
You’ve probably heard the term “carb loading,” which means filling your face with delicious carbohydrates to give your body enough energy for serious exercise. (In other words, pre-workout food.) But is it necessary?
Once again, science is as tangled as a drunken spider web. It also depends on what you mean by sport.
When you look at weight training, there isn’t a lot of information out there. Some research from 2013 suggests that whether you eat before or after your workout doesn’t make much difference in your ability to exercise those swollen muscles.
Similarly, in a 2018 review, researchers found no association between eating and performance during brief aerobic exercise of less than an hour.
However, the review found that adding carbohydrates before exercise could improve results if the exercise lasted longer. So if you are planning a 30 mile run, it might be a good idea to eat beforehand.
So … WTF is running?
Okay, take a breath. We have you
Overall, it seems that if you are planning on short, gentle exercise, previous eating should not cause vomiting-related side effects, but it is also unlikely to improve your performance.
If you’re looking to burn fat, exercising without food seems like the best plan – but the benefits may not last in the long run.
For endurance-conscious people whose idea of exercise is more like a marathon, eating before training (or even during a run) can help increase endurance, but it can also increase the risk of indigestion.
It is a good idea to wait a few hours after eating before starting your workout. It takes 2 to 3 hours for your stomach to empty food into your small intestine.
Although complete digestion takes much longer, 1 to 2 hours after a meal and 30 minutes after a snack is enough for most people to feel good and avoid digestive problems. But here, too, it is not quite as simple as “you have to wait that long”.
What you eat and the intensity of your planned activity will affect the waiting time. Eating a huge meal will take longer to digest, which means you should wait longer to exercise.
Also, in addition to thinking about the amount, you need to think about what you are eating. Your body digests nutrients at different rates. A meal high in fat, fiber, and animal protein usually breaks down more slowly than a high-carbohydrate meal.
But everyone’s digestion is different. The best plan is to listen to your body, see how you are feeling, and do what is good for you. Some people like to exercise right after you eat, but you may have to wait a few hours before you can get started.
As a rule, if you plan on gentle exercises like walking, it is probably okay right after you eat. But if CrossFit is more your thing, you might want to pause for up to 3 hours after eating.
There are no studies comparing the safety of different sports after eating.
But in general, the more intense the exercise, the more likely it is to have unpleasant side effects after eating. Chances are, at 50 burpees, you will feel extremely burpy. Or nausea. Or worse.
If you can only exercise right after you eat, you should probably stick to something gentle like yoga (without a headstand), walking, or golf. Perhaps now is the time to start archery or competitions in rain boots.
For some people, lifting weights is a safe post-meal activity. If weights are your thing, you can try them out and see how it works for you. It’s best to start small and work your way up, because there are no hard and fast rules and it all depends on your metabolism, your biology and your movement patterns.
If you are planning on doing an exercise that makes you extremely out of breath or makes your stomach spin, you should probably skip doing this for a few hours after you have finished eating.
While the evidence is a bit bumpy, eating right, and not just any old thing, could help increase the caliber of your workout while minimizing muscle damage.
It’s important to prioritize two nutrients. You are going to need some good ol ‘carbohydrates because they are your body’s main source of energy. And some protein will help with tissue repair, because building muscle is hard work and you need to maintain that mass.
With that in mind, here are some examples of high protein and high carbohydrate snacks:
How Much Should You Eat Before Exercising?
If you have big sporting ambitions, consider smaller snacks. Leaving yourself just 30 minutes before a workout will make sure you’re not overeating that is heavy on your stomach.
Your stomach isn’t that big, despite what the fourth slice of pizza tells you. Its capacity will depend on your height and weight, but a typical stomach is only 13 inches wide, 15 inches thick, and 10 inches high, and can hold about 1 liter.
Keep that in mind when choosing your pre-workout snack and try to choose something that is nutrient-dense but smaller than your fist.
Eating before exercise does not affect everyone. But everyone is different, and you should be aware of the potential for digestive symptoms and sub-par performance if you eat before a workout.
Studies show that 30–50 percent of athletes experience problems such as gas, nausea, vomiting, and diarrhea. Cramps and sluggishness are also possible and can affect performance.
Endurance runners are particularly at risk – up to 90 percent suffer from exercise-related digestive problems. Cyclists are also particularly at risk for bowel problems because of their position, which increases pressure on the abdomen.
What you eat can be just as important as when you eat.
A small 2014 study of 10 male participants found that eating a high-carb, high-protein meal before playing basketball caused gastrointestinal side effects, but the presence of protein reduced muscle damage. Side effects were not as common in men who ate a high-carbohydrate meal with no protein.
While experts usually recommend consuming protein and carbohydrates before training, experiment and see which combination of nutrients works best for you.
To eat or not to eat before exercise: that is the question. And there doesn’t seem to be a one-size-fits-all answer. Exercising without eating can increase the amount of fat your body burns for fuel, but overall it may not result in a significant loss of body fat.
There isn’t much evidence that eating before short-term exercise makes a significant difference in performance. But when you’re planning a plan that will deplete your energy stores, eating can be beneficial.
To avoid or minimize side effects, wait 1 to 2 hours after a meal or at least 30 minutes after a snack.
The main takeaway is that everyone is different and you should listen to your body to find out what suits you.
If you feel weak and tired while exercising, maybe snacking could increase your energy levels. If you feel sick eating before you exercise, allow more time between eating and exercising. You can also consider what nutrients to consume and reduce protein and fiber.