“Nutrition is so important but often overlooked,” said Stacy Sims, exercise physiologist, nutrition scientist and co-founder of Osmo Nutrition, which makes gender-specific nutrition products. “Putting it as a cornerstone of your training plan is essential.”

Women are not small men, Sims said, with differences stemming from the normal, monthly hormone fluctuations in a woman’s body. During the first 14 days of a woman’s cycle–roughly beginning with the onset of menstrual bleeding– hormone levels are low, and women respond similarly to men. Around day 14, known as the luteal phase, increased levels of estrogen and progesterone change the way a body metabolizes nutrients, altering hydration and dietary needs.

During the luteal phase, women’s bodies burn more fat and decrease dependency on glycogen stores, unlike men.  Cutting carbohydrates can reduce performance and prompt the body’s starvation mechanism, which encourages weight gain.

“Women need to stay on the carbohydrate intake in the high hormone phase,” Sims said, to prevent depletion. “If you are craving carbohydrate, then temper your diet to match that.”

Nutritionist Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center agreed.

“During that phase, a woman’s calorie needs might be a little bit higher,” Bonci said, but by no more than 200 calories. She recommends eating high-quality carbohydrates and remembering that women have different caloric needs than men. Active women need somewhere between 18 and 23 calories per pound while men need 20 to 27.

Proper nutrition during exercise helps harness potential, they said.  Cycling coach, retired professional racer, and current U.S. road and time trial national champion Alison Powers agreed. She often sees calorie conscious women skimping before just when nutrition matters most. This backfires long-term.

“Women eating while exercising, and eating for exercise, will in the long run help them achieve the weight they want,” Powers said, and she gives her athlete’s specific recommendations.

“If you eat every 30 to 45 minutes during a ride…then you can keep riding stronger instead of getting tired at the two and a half or three hour mark and bonking,” Powers said. Losing energy early hampers quality of training.  She advises eating appropriately  immediately before, during and after workouts, then cutting back at dinner or skipping a bedtime snack if necessary.

Post-exercise nutrition stimulates recovery and should be tailored to women, too. The standard recommendation of a 4-to-1 or 3-to-1 carbohydrate to protein ratio doesn’t work in the high hormone phase since women don’t shift into muscle rebuilding as easily. A quick shot of protein can enhance that shift.

“A big concern is getting 25 to 30 grams of protein within 30 minutes of stopping training,” Sims said. A single serving of Greek yogurt would work and can be thinned with almond milk to preferred consistency.

Likewise, most post-ride recovery foods and drinks are geared toward men’s caloric needs, Bonci said, and women should think a “petite snack”.

“We’re not talking about a bagel the size of an SUV tire,” Bonci said, or giant energy bars. A normal meal within the next few hours and before a woman’s short recovery window closes also helps.

High hormone levels impact hydration, too. Women should better pre-hydrate and increase sodium intake prior to exercise, then continue with .15 to.18 ounces of fluid per pound of body weight each hour during intense or race efforts.  While natural fat stores can at times compensate for poor nutrition, hydration is different.

“You have no stored hydration anywhere. If you dehydrate … you’re done,” Powers said.

Most engineered sport foods and drinks grew out of studies performed on men, Sims said, since women’s hormonal fluctuations were deemed too difficult to study.

“Almost everything that is known about sports nutrition is through research done on 18- to 22-year-old college men,” Sims said, and many of the drinks, gels and foods can cause women stomach upset because of their different metabolic process.  Eating “real” food tends to serve women better, Sims said, but Sims and Bonci hope that changes in the future.

“Women are fierce competitors, and we really need to be able to take our place equally at the training table,” Bonci said.

Women can combat some hormonal changes using supplements, as well.  Sims recommends magnesium, zinc and omega-3 fatty acids before bed in the five to seven days before a woman’s period starts. This counteracts bloating and cramping.  Taking five to eight grams of branched-chain amino acids 30 minutes before exercise can help women combat increased central nervous system fatigue and increase muscle repair.

Dialing in diet works best in a cyclist’s offseason, Bonci said, because it takes time and effort. Changing nutrition during peak training and racing can overload a rider’s plate.

“So it needs to be worked out ahead of time, then it can become habit and routine,” she said. It also affords women a chance to listen to their bodies and hear what works for them. They can then make small tweaks and reap big rewards.