Nutrition For Fit Females: Why You May Need To Eat More

Most people need to eat fewer calories. But if you’re a fit woman or female athlete, you may need more!

A new review found that many female athletes suffer from low energy availability (LEA) when calorie intake is too low to support training. LEA can lead to poor recovery and performance, changes in hormones, and the loss of period. LEA can also increase risk of bone fractures, injuries, and longer term, osteoporosis.

The prevalence of LEA varies from 2 percent among club sport athletes to 77 percent in professional ballet dancers. Lack of calories affects as much as 36 percent of female high school athletes and two-thirds of female college athletes.

Individual sport athletes versus team sports and those in endurance sports have a higher prevalence of LEA. Additionally, female athletes tend to have significantly lower energy intake relative to body mass than men—a fact that is not warranted by differences in energy metabolism between the sexes. Although women do have different substrate needs during training, burning more fat and less carbohydrate than men, energy needs are similar per pound of body weight. Simply, many women need to eat more.

Why aren’t female athletes eating enough?

Preoccupation with body image and the pressure to achieve a low body fat percentage is one reason. But it’s not the only one. Scientists note that increased training loads and appetite suppression from intense training can lead to LEA. For example, a female athlete who ramps up training volume without increasing calories can easily achieve a calorie deficit of 500 to 1,000 calories a day.

And some athletes will restrict food to reduce GI symptoms in subsequent training sessions. Additionally, intense training blunts appetite. Similarly to patients with anorexia, fit, lean women have been found to have high levels of the appetite-suppressing compound peptide YY.

Changing diet composition also increases risk of LEA. For example, switching to a plant-based diet or trying a keto diet can lead to a drop in calories while also compromising nutrition that affects physical performance. The menstrual cycle also impacts appetite and macronutrient needs. Fluctuations in hormones that follow the cycle affect fuel use during training, impacting fat and carbohydrate burning.

How much of an impact can insufficient calories have on performance?

There’s a lack of research on how lack of calories impact performance in women. We do know that when elite rowers increased their training load by 21 percent without a subsequent change in calories or nutrition over a 4-week period they experienced a 5 percent decrease in resting metabolic rate, a slower 5 km time trial performance, and greater fatigue. Metabolic rate dropped because as the body senses a lack of energy, it spares energy, lowering the amount of calories burned. Lean muscle mass is also lost, compromising strength and increasing risk of injury.

A second study in elite female swimmers suffering from LEA who weren’t getting their periods had a 9.8 percent decrease in performance over a 12-week season. In contrast, the athletes who remained cyclic and consumed sufficient calories improved performance by a respectable 8.2 percent by the end of the season.

Solutions To Low Energy Availability

Solving LEA isn’t as simple as eating more. Calorie intake and macronutrients need to be varied based on goals and training needs. Additionally, food intake often has an emotional element that can make changing diet a challenge. What follows are five steps to optimizing nutrition for fit women.

#1: Do A Food Journal

The first step to overcoming LEA is identifying that it is a problem. Many fit women are so used to living in an energy deficit that they don’t realize their performance is compromised. Doing a food journal to assess calorie intake and macronutrients (carbs, fat, and protein) is the first step to ensuring you are getting enough calories. Food journals should cover at least three days and include higher and lower volume training days.

#2: Work With An Experienced Professional

Working with a nutritionist experienced in advising female athletes will allow you to fine tune your nutritional needs. Mainstream nutritionists rarely have a thorough understanding of an athlete’s training load, including the variation in volume and intensity that occurs seasonally and especially on a daily basis.

#3: Identify Calorie Needs

Scientists recommend that female athletes never go below 30 cal/kg of bodyweight a day, with ideal intakes being between 39 to 44 cal/kg bodyweight/day. Endurance athletes or those who burn large volumes of energy during training may need to add exercise energy expenditure on top of that. For example, a 55 kg middle distance runner would have baseline energy needs ranging from 2145 to 2420 a day. Running 5 to 6 miles a day could bump that up to 2745 to 3020.

#4: Time Nutrition To Match Training Volume

Calories and the overall nutrition plan should be periodized to match daily training volumes. Higher calorie intake is needed on intense or high-volume days, whereas recovery days should supply lower calories. Macronutrients can follow a similar variation with higher carb and protein intake on training days and lower carbs on off days.

#5: Consider Appetite & Psychological Factors

When increasing energy intake to coincide with higher training volumes, appetite and psychological factors should be considered. Appetite doesn’t automatically increase with training volume, and if a female athlete has a history of food restriction, they are unlikely to bump up calories sufficiently. Using foods that are more energy dense and promoting liquid-based recovery options with high-quality supplementation can be a successful strategy to increase energy intake.