Training hard for a marathon, Barbara would alternate one- to two-hour hard runs with easy jogs to give her muscles a rest, but the 40-something woman couldn’t understand why these short runs were as taxing as long-distance treks, leaving her muscles sore and exhausted.
It all came together when Barbara met with Mary Ellen Kelly, a registered dietitian at Harvard’s Brigham and Women’s Hospital. She confessed that she usually didn’t eat anything after training to encourage fat burning. But her zero-food strategy meant she was sacrificing the strength and endurance needed to train effectively.
“The long runs took a toll on her and she found it incredibly difficult to run sprints on such an energy and protein-deprived diet,” Kelly recalled.
Barbara’s example highlights a dramatic difference between men and women. After exercise, our bodies require completely different approaches to replenish what is lost and promote muscle recovery and growth. Women should ideally refuel within 30-45 minutes after exercise, while men may need up to three hours to complete the same task. Continually ignoring this need can lead to symptoms of low energy, such as fatigue and soreness.
As Barbara learned, “when you’re chronically fuel deprived, it’s very hard for your body to optimize recovery,” Kelly says.
Hormonal factors
Exercise is the best stress for women and men because it gets your heart rate up and your muscles working harder, but to overcome that stress you need to fuel yourself properly.
But that’s where the similarities end. Why do women have such a short fuel refueling time? The difference lies in hormonal differences between men and women, says Beth Frates, M.D., director of lifestyle medicine and wellness at the department of surgery at Massachusetts General Hospital, which is affiliated with Harvard University.
Progesterone is the main factor that exacerbates muscle breakdown after exercise in women. This effect is even more pronounced in pre- and post-menopausal women. If you leave your muscles in a state of breakdown without supplementing with protein, or if you only consume protein at the beginning and end of your day, you are likely to feel fatigued, sore, and not perform at your best.
“Women need to replenish protein sooner to prevent this breakdown,” says Dr. Frates.
During the luteal phase of the menstrual cycle (about one week before menstruation begins), women may crave more carbohydrates and feel the urge to eat more.
“If you feel a little hungry, it’s not just your imagination – your body is actually craving it,” Kelly says. “Being aware of your cycle, listening to your hunger cues and eating a little extra may help your training.”
Protein packing strategies
Consume at least 70 grams of protein throughout the day to ensure you start your workout well-fueled, “which means your muscles are well hydrated and ready to work,” says Kelly.
After exercise, you should consume around 20 grams of protein within 45 minutes, and pair it with carbohydrates if you don’t plan on eating again within an hour or two.
Protein-rich food choices include:
- 1 cup Greek yogurt
- 3 ounces of chicken, turkey, salmon, or steak
- 1 scoop of whey protein powder
- Ready-to-drink protein shake.
Even a large glass of chocolate milk can provide plenty of the protein, carbohydrates and electrolytes your muscles need after exercise, Kelly says.
If, like Barbara, you’re looking to burn fat through exercise, it’s possible to achieve your goal and fuel properly afterward. Kelly says you just have to be strategic about it so you don’t sacrifice strength in the process. How? Aim for a calorie deficit at other times of the day, not post-workout. Kelly suggests watching your portion sizes and limiting alcoholic beverages.
“If you’re doing light exercise, like going for a walk or 20 to 30 minutes on the elliptical, you probably don’t need to apply the principles of intentional nutrition,” she says, “but if your exercise is intense and your ultimate goal is weight loss, pay attention to your overall nutritional patterns.”
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