It’s a common question — should i eat breakfast before working out? The answer is that it depends on the type of workout you are doing and your body weight. I’ve put together my own little summary. Many people assume that they should eat breakfast before working out, but this isn’t necessarily the case. It’s especially tricky when you start talking to other people, because their ideas about what is best for your body will be quite different from yours.
Breakfast Before or After a Workout?
The premise: Breakfast is billed as the most important meal of the day—but you may want to hold off on eating it until after your daily workout. Researchers in Belgium set up a six-week study to determine if the order of men’s morning routines would make a difference in terms of weight loss and other health aspects. “We hypothesized that training in the fasted state would be a better strategy to improve fat metabolism,” says the study’s lead author Karen Van Proeyen, Ph.D. “However, we were rather surprised that almost all measured parameters were more beneficially affected following a training program before breakfast, compared with a similar training session after breakfast.”
The set-up: The researchers recruited 28 healthy, active men and tweaked their daily diets to include 50 percent more fat and 30 percent more calories (to enhance the effect). The men were then broken into three groups. The first group endured no exercise at all, while the other two groups were both given grueling morning exercise routines. Four times a week, they ran and cycled at intense levels. However, of those two groups, one worked out after a carbohydrate-rich breakfast and drank sports drinks throughout their workout. The other group drank only water and ate breakfast after hitting the gym.
The results: The group that didn’t exercise at all gained an average of more than six pounds (we’re surprised it wasn’t more!). They also developed unhealthy conditions that are often precursors of diabetes including an insulin resistance. The men who ate breakfast before exercising also gained weight (although only about half as much as the first group) and similar cautionary diabetes signs. The group that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. They also burned the extra dietary fat more efficiently.
Is it safe to work out on an empty stomach?
While there’s some research to support working out on an empty stomach, it doesn’t necessarily mean that it’s ideal. When you exercise on an empty stomach, you may burn valuable energy sources and have less stamina. Low blood sugar levels may also leave you feeling lightheaded, nauseous, or shaky.
Another possibility is that your body will adjust to continually using fat reserves for energy, and start to store more fat than usual.
Does working out on an empty stomach help you lose more weight?
Exercising on an empty stomach is what’s known as fasted cardio. The theory is that your body feeds on stored fat and carbohydrates for energy instead of food you’ve recently eaten, leading to higher levels of fat loss.
Research from 2016 points to the benefits of working out in a fasted state in terms of weight management. The study among 12 men found that those who didn’t eat breakfast before exercising burned more fat and reduced their caloric intake over 24 hours.
Some research dispels this theory. A 2014 study on 20 women found no significant differences in body composition changes between groups who ate or fasted before working out. As part of the study, researchers measured body weight, percent body fat, and waist circumference over four weeks. At the end of the study, both groups were shown to have lost body weight and fat mass.
More in-depth research over a longer period of time is needed to expand upon these findings.
Working out on an empty stomach could also lead your body to use protein as fuel. This leaves your body with less protein, which is needed to build and repair muscles after exercise. Plus, using fat as energy doesn’t necessarily mean that you’re going to lower your overall body fat percentage or burn more calories.
Secret Side Effects of Exercising Before Breakfast, Says Science
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You might get better results from your workout
Your body might have more strength and endurance in the morning to handle cardio. A 2013 review of research found that people’s aerobic endurance may be greater in the morning, and that they tend to hit a higher heart rate during morning workouts than during evening ones. And for some exercise moves you should ignore at any time of day, don’t miss The Worst Abs Exercises You Shouldn’t Do After 40.
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It will help wake you up
Your body’s levels of cortisol—the “stress” hormone that impacts our energy levels—are naturally higher in the morning, and tend to slough off throughout the day until bedtime. Moderate-to-high intensity exercise can also (temporarily) elevate cortisol levels. By working out first thing in the morning, when your cortisol levels are already elevated, you give yourself an extra spurt of caffeine-free energy that can help power you through the morning.
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It may help burn fat
If weight management is one of your fitness goals, consider prioritizing the morning workout. A small 2015 study found that men who exercised before breakfast enjoyed increased fat oxidation (aka the burning of internal fat stores for energy) compared to people who did their workouts at other times of day. A 2016 review of studies also found that exercising in a fasted state—such as in the morning before breakfast—tends to burn more fat than exercising after eating a meal with carbohydrates. However, the researchers note that it’s unclear if these effects persist in the long-term.
What to Eat Before and After Workouts
Of course, what you eat before and after a workout is just as important as when. Performance-oriented athletes with a goal of fat loss should aim for a minor daily calorie deficit and emphasize protein in their diet from foods like Greek yogurt, eggs, chicken, seitan, tempeh and fish to preserve muscle while burning body fat.
And those who prefer to eat before a workout probably know that a fatty meal of steak and eggs with hash browns makes for an uncomfortable workout session. Instead, choose a lighter, easier-to-digest meal that gives you enough energy to push harder and faster without feeling sluggish.
In order to ensure the meal feels comfortable in your belly during exercise, eat a meal or snack one to two hours before your workout and avoid high-fiber and high-fat foods such as beans, cruciferous vegetables or fried foods. Prioritize easy-to-digest carbs and pair it with a little bit of protein to help accelerate recovery.
Some great pre-workout snacks or meals include:
- Whole wheat toast with peanut butter
- A large banana and a hard-boiled egg
- Oatmeal with berries and nut butter
- Pretzels with hummus
- Dried edamame and dried fruit
- Sweet potato toast topped with nutritional yeast
Whether you’re exercising with or without breakfast, the post-workout meal is non-negotiable. Choosing the right foods optimizes recovery and improves muscle mass creation. Aim for 15 to 25 grams of protein after exercise (4-6 ounces of meat, fish, Greek yogurt or 3/4 cup beans or tofu).
Pair with carbohydrates to refuel glycogen stores and rebuild muscles. Remember that while your body is readily able to burn carbs post-workout, choosing a carb source that’s high in fiber keeps you fuller longer while feeding hungry muscles. Great high-fiber carbs include quinoa, beans and farro.
Some healthy post-workout options include:
- A protein shake blended with a large banana
- Rice and beans topped with nutritional yeast for some extra protein (or a palm sized portion of salmon)
- An omelette with a sweet potato
- A sandwich made with high-fiber bread and turkey or mashed chickpeas with sliced avocado
The 4 Worst Foods to Eat Before a Workout
1. High-Protein Foods
Skip the steak before you hit the gym.
While high-protein foods can satiate your stomach and stave off hunger, getting too much of the macro can mean sluggish digestion. Plus, eating protein-only foods means you’ll miss out on the energy-rich carbs that really power you through tough workouts, Bruzina says.
Not to mention, exercising when food is still jostling in your stomach can cause major discomfort. Just think: A tummy stuffed with protein can make you feel heavy and weigh you down.
You should have a bit of protein — aim for just 10 to 20 grams — coupled with a healthy source of carbs for sustained energy.
Or think of it this way: Your meal or snack should contain at least 75 percent of total calories coming from carbs and no more than 25 percent coming from protein,
2. High-Fat Foods
Like protein, fatty foods take a long time to digest, Bruzina says.
That means they stick around your stomach for hours. And while your body’s busy digesting, more blood flows to your GI tract to aid the process, so there’s less oxygen going to your muscles.
In other words, your muscles don’t get the stuff they need to perform their best.
The takeaway: Before you exercise, steer clear of greasy burgers and pizza as well as too many healthy fats like nuts and avocado.
3. High-Fiber Foods
From legumes to whole grains and veggies, fiber-filled foods benefit your heart, help with weight loss and are good for your gut. But a big bowl of black bean soup for lunch may hinder your workout later in the day.
Indeed, high fiber foods may cause gastrointestinal discomfort, resulting in gas, bloating or cramps, Bruzina says.
Be especially aware of fiber-rich cruciferous veggies. Nothing brings on the belly bloat like broccoli, Brussels sprouts and bok choy.
Like beans, veggies from the cruciferous family contain an indigestible sugar called raffinose, which feeds the bacteria in your colon that produces methane gas.
All this to say, you can’t focus on the gym if your stomach is swollen with gas and you’re booking it to the bathroom every few minutes.
But don’t stop eating nutritious fibrous foods — getting enough daily fiber is essential for overall health (women should aim for 25 grams per day and men, 38 grams, per the Academy of Nutrition and Dietetics). Simply limit your intake for a few hours prior to exercise.
4. Spicy Foods
Love food with a kick? You might need to scrap the Sriracha sauce and postpone the jalapeno peppers until post-workout.
For some individuals, spicy foods can cause problems like gastrointestinal distress, heartburn or acid reflux during exercise, Bruzina says. Dealing with a burning sensation in your throat or an upset stomach is the last thing you need when you’re exercising.
Fasted Vs. Fed Exercise
The Effects of Fasted Exercise on Weight Loss and Body Composition
A 2017 systematic review and meta-analysis of 5 studies published in the Journal of Functional Morphology and Kinesiology found no correlation between training in a fasted state and greater weight loss. The studies included a total of 96 adult participants who were split into two groups: (1) participants who exercised after an overnight fast and (2) participants who exercised in a fed state, after consuming a standardized meal and then measured in terms of body mass and/or body composition. The results? The effects of fasted exercise versus fed exercise on weight loss were found to be trivial.
The study also found that fasted exercise had little to no positive (or negative) effects on body composition, or the amount of fat and muscle in the participants. In other words, fasted exercise isn’t the end-all-be-all to fat loss, either.
Fed Workout
If you just can’t work out on an empty stomach, that doesn’t mean your fat-loss efforts are doomed. A November 2017 review in the Journal of Functional Morphology and Kinesiology found that despite increases in fat burning, exercising fasted did not result in greater fat loss than exercising after breakfast. Ultimately what matters is ending the day in a calorie deficit (burning more calories than you consume).
And if your goal isn’t fat loss, but more aligned with performance goals, you should consider eating a meal before important or difficult training sessions. According to a 2016 position paper published in the Journal of the Academy of Nutrition and Dietetics, carbohydrates improve the intensity and duration of workouts while training fasted compromises the quality of the athlete’s workout and training.