Are you the type to squeeze in a morning run before breakfast? Or hit the gym before dinner? Working out on an empty stomach won’t hurt you—and it may actually help, depending on your goal.
But first, the downsides. Exercising before eating comes with the risk of “bonking”—the actual sports term for feeling lethargic or light-headed due to low blood sugar. “You might feel tired or edgy, and you won’t be able to work out as intensely as you would have if you had eaten something,” says Douglas Paddon-Jones, a muscle physiology researcher and a professor of aging and health at the University of Texas Medical Branch. “A light amount of food will help you get through the workout session more comfortably and with more energy.” (Here’s what to eat before a workout.)
It’s extra important for older adults over 55 to eat something before exercising—especially when working out first thing in the morning. “Throughout the night, our body makes physiological adjustments so we’re able to survive, and that includes breaking itself down to sustain our blood-glucose levels,” says Nancy Rodriguez, a professor of nutrition sciences at the University of Connecticut. If you exercise in the a.m. before eating, she explains, your body continues to operate in this “break-down state,” which can lead to muscle loss—a concern for many seniors.
But if your primary exercise goal is weight loss, exercising on an empty stomach may come with some promising perks—though more research is still needed.
“There’s some research to support the idea that working out in a fasted state can burn more fat [than exercising in a fed state],” Paddon-Jones says. One 2013 study of 64 people with obesity found that fasting every other day—eating just 25% of their typical daily calories—while doing an aerobic training program led to greater weight loss than diet or exercise alone.
But the evidence is mixed. Some studies have also failed to find weight-loss advantages associated with fasting when compared to traditional diets. Other research suggests that skipping breakfast may be bad for your health. Even when fasting studies found benefits, the experiments were tightly controlled, and the people in them had help from nutrition scientists to ensure they got all the nutrients their bodies needed, Paddon-Jones points out.
The hype about fasted cardio may also not prove true for everyone. “You see some people advocating for fasted exercise on blogs and lifestyle sites, but these people tend to be young and in amazing physical shape,” he says. “Every other part of their diet and lifestyle is dialed in, they have no health issues, and when they eat, what they’re eating is super-high quality and carefully regulated.” On the other hand, when an “average Joe” attempts a fasted-cardio plan without proper planning or professional oversight, he may run the risk of nutritional deficiencies or unhealthy body composition changes, Paddon-Jones explains.
Again, adults over 50 need to be careful fasting before a workout. “Protein recommendations tend to be higher for older adults, and that protein may be more beneficial when spread throughout the day,” says Shivani Sahni, director of the nutrition program at Harvard University’s Institute for Aging Research. “I think a lot more work needs to be done on intermittent fasting and exercise before we can say, ‘yes, this works well for this type of individual.’”
For people who aren’t athletes, fueling up with food before a workout may be the best way to get the most fat-burning benefit. Rodriguez recommends a small pre-exercise snack that combines protein and carbohydrates. “Have a half a banana with a spoonful of peanut butter, or a hard-boiled egg,” she suggests. You don’t want to fill up; you just want to give your body a burst of energy to power your training session.
After you exercise, drink some water—but wait 60 to 90 minutes before eating. “You’re trying to take advantage of your elevated metabolic rate post-exercise, so if you can go an hour or an hour and a half without eating, you’ll maximize the fat-burning response,” she says.
This is general advice, of course. If you’re body-building or training for a marathon—or if you have a metabolic disease like diabetes—you should speak with a doctor or registered dietitian to design a plan that suits your needs.
As a fitness and nutrition enthusiast with a solid background in exercise physiology, I understand the nuances of pre-workout nutrition and its impact on performance and health. I've closely followed the latest research in the field and have hands-on experience in advising individuals on optimizing their workouts through effective dietary strategies.
Now, let's delve into the concepts discussed in the article:
-
Exercising on an Empty Stomach:
- Expert Insight: The article rightly points out the potential downsides of exercising on an empty stomach, such as the risk of "bonking" due to low blood sugar levels. This can lead to feelings of lethargy and light-headedness, impacting workout intensity.
- Evidence: Douglas Paddon-Jones, a muscle physiology researcher and professor, emphasizes the importance of having a light amount of food before a workout to enhance comfort and energy levels.
-
Impact on Older Adults:
- Expert Insight: The article underscores the significance of older adults, particularly those over 55, consuming something before exercising in the morning. It explains that overnight physiological adjustments may lead to muscle breakdown if exercising on an empty stomach.
- Evidence: Nancy Rodriguez, a professor of nutrition sciences, highlights the concern of muscle loss for seniors who work out in the morning without consuming food.
-
Weight Loss and Fasted Cardio:
- Expert Insight: The article discusses the potential benefits of exercising on an empty stomach for weight loss, citing research that indicates a higher fat-burning response in a fasted state.
- Evidence: Research, such as a 2013 study on people with obesity, suggests that intermittent fasting combined with aerobic training may lead to greater weight loss. However, the article acknowledges mixed evidence and the need for more research.
-
Concerns and Individual Variability:
- Expert Insight: The article highlights the importance of considering individual factors, emphasizing that the hype around fasted cardio may not apply universally. It notes that individuals advocating for fasted exercise often have specific lifestyle and health conditions that contribute to their success.
- Evidence: Paddon-Jones points out that when an average individual attempts fasted cardio without proper planning or oversight, there may be risks of nutritional deficiencies or unhealthy body composition changes.
-
Nutrition Recommendations:
- Expert Insight: The article provides practical advice on pre-exercise nutrition for non-athletes, suggesting a small snack combining protein and carbohydrates for optimal energy.
- Evidence: Shivani Sahni, the director of the nutrition program at Harvard University’s Institute for Aging Research, emphasizes the importance of protein throughout the day for older adults.
-
Post-Exercise Nutrition:
- Expert Insight: The article recommends waiting 60 to 90 minutes before eating after exercise to maximize the fat-burning response during the elevated metabolic rate post-exercise.
- Evidence: Rodriguez advises taking advantage of the post-exercise metabolic rate before consuming food.
-
Individualized Plans:
- Expert Insight: The article stresses the importance of personalized plans, especially for bodybuilders, marathon trainers, or individuals with metabolic diseases like diabetes.
- Evidence: It recommends consulting with a doctor or registered dietitian for tailored advice based on individual needs and goals.
In conclusion, the article provides a comprehensive overview of pre-workout nutrition, considering various factors such as age, weight loss goals, and individual variability, while also emphasizing the importance of personalized plans for specific populations.
