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To Eat or Not to Eat? John Heiss on Pre-exercise Nutrition

John Heiss, Herbalife Senior Director Sports and Fitness and dedicated endurance athlete, is in a perpetual state of experimentation when it comes to sports nutrition and training methodologies. He has extensive experience in fasted cardio, in which you work out on an empty stomach after not eating for typically five hours or longer. Though this method has skyrocketed in recent popularity, there is plenty of debate on the merits. “The general thinking is that by not eating food, your body tends to burn stored fat for energy, preferentially over the food you just ate,” says Heiss. “The thinking is pretty sound: your body will certainly burn the food you just ate, especially any carbs, before turning to stored fats for energy. But how does this translate into real-world application of results you can see? Training is a lot more than just trying to burn calories, so the answer is complicated.”

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Thinking Long Term

According to Heiss, weight loss, or fat burning, needs to be considered in a long-term context, such as a 24-hour or weekly energy balance of calories in and calories out. A successful weight-loss program should be long-term and combine healthy eating and exercise. Looking only at total calories burned, or the types of calories burned during a workout window, is over-simplifying the equilibrium of body composition. “A good example of this is High Intensity Interval Training (HIIT), where athletes might do ten maximal efforts lasting 20 seconds each with only 30-60 seconds of rest in between,” says Heiss. “The total number of calories burned during this session is quite low, but the long-term (24 hour) increase in metabolism is quite significant.” This type of training elicits adaptations that are different from conventional long slow-distance workouts, but are also advantageous for overall fitness. This somewhat contradicts the advice of many scientists and nutrition advisors who recommend long, stead-state aerobic exercise to help burn fat or calories. Though there is not yet consensus opinion and further scientific research may change the conclusion, recent reports show that a mixture of exercise types is probably best. This includes some steady state/low-intensity work, some HIIT sessions and, perhaps most importantly, resistance training (weight training, even if doing simple exercises like body-weight squats and push-ups), which can make a large contribution to calories and fat burned. There also appears to be some cognitive benefits to exercise, specifically from resistance training.

“My general advice for most people is to do a mixture of workout types each week,” says Heiss. “They can try one resistance day, one cardio day and one high-intensity day to start.” So, what should they eat before these types of workouts? In Heiss’ opinion, it isn’t right or wrong to eat or not eat before exercise. He suggests you mix it up, starting on an empty stomach before some workouts and eating before others. When you train in the fasted state, you train a different metabolic pathway than you do in the fed state. The bottom line is that, depending in which state you train, you will have differing results. “I see too many people overdoing it,” says Heiss. “They’ll eat breakfast, have a pre-workout drink, a sports drink and then a recovery shake, all for a 90-minute cardio session. Finding the right balance between exercise and nutrition is key.”

Cardio Vs. Weight Training

For most people who do one to two hours of typical cardio, Heiss suggests they err on the side of actually eating less before exercise and shifting the calories that they would have consumed before and during the workout to a post-workout shake. One reason for this is that exercise while fasting can help to burn fat efficiently. When weight training, he usually recommends having either a pre-workout drink with caffeine and nitric oxide precursors, such as Herbalife24® Prepare or a protein shake, followed by a high-protein shake post-workout. Protein ingestion, both before and after training, supports increases in lean muscle mass. As for Heiss’ personal nutrition regimen, most of his workouts are done fasted. “I wake up early and get in a run or ride before work,” he says. “Since I’m doing a 60-minute run or a two-hour bike ride at moderate intensity, I don’t need the calories. After the workout, I’ll come home and make a large recovery shake that doubles as breakfast. This almost always incorporates Herbalife24® Rebuild Strength. On the weekends, when I usually do longer and more intense runs or rides, I’ll either eat some breakfast or just start eating as soon as I start working out. On those days, I might consume Herbalife24® CR7 Drive, Herbalife24® Prolong and Herbalife® Protein Bar Deluxe.”

Ultimately, Heiss notes that having food before a workout isn’t going to undo any of the major long-term health benefits, and conversely, not eating before won’t magically burn away fat either. There are many advantages to eating before exercise, such as that you can exercise at a higher intensity for longer, resulting in greater fitness and health gains in the long run. What matters most is that regular exercise and an overall healthy eating pattern will have the biggest impact on your overall fitness goals.

Heiss’ Fasted Cardio Quick Tips

  • Work up to exercising on an empty stomach by gradually increasing exercise duration. Be sure to keep the intensity low at first – when doing HIIT, the real benefits of fat burning and aerobic adaptations occur throughout the span of the entire day, so the amount of fat burning that actually occurs during exercise is pretty minimal.
  • Don’t start so hungry that after your workout you go on a binge and consume more calories than you burned.
  • Focus on eating enough before your workout so that you can have a high-quality workout.
  • Mix in some sessions where you start off a little hungry. Be sure to have a good high-quality protein shake afterward.