From a purely scientific perspective, we eat in order to provide our bodies with an adequate and balanced supply of all the raw materials they need to stay fueled for optimal function—for as many hours as possible. In order to achieve this energy-based goal, it’s important to understand how macronutrients work together and why their ratios matter. 

While it would make things a lot easier, there aren’t really any hard and fast rules for determining exactly how many carbohydrates, proteins, and fats a woman should be eating. Her age, body composition, genetics, and training routine all influence her metabolism. Some women can achieve their health, performance, and recovery goals by following a lower-carbohydrate, higher-fat diet. Others thrive on a more complex carbohydrates and fewer fats. Almost all active women feel and perform better with at least a moderate amount of protein. If you are a female athlete who has difficulty consuming enough dietary protein (about 2 grams of protein for every kilogram of bodyweight), consider supplementing your diet with a high-quality protein powder like Pure Clean Protein, which offers 25 grams of easily-digestible protein. Or FundAminos, which bypasses the digestive process entirely to offer the equivalent of 40 grams of dietary protein.

 Exploring the concept of fat adaptation may offer some key insights into how you should be eating for optimal health and performance. 

 What—exactly—is fat adaptation? It’s a metabolic state in which the body recognizes both dietary and stored fat as its primary source of energy. Being able to mobilize and utilize stored fat for energy can reduce the body’s dependence on glycogen (carbohydrates stored in the form of sugar), which can be a huge benefit for competitive endurance and ultra-endurance athletes. While many female athletes don’t burn fat as a primary fuel source because they’ve become accustomed to following a higher carbohydrate diet, becoming fat adapted can benefit athletes and non-athletes alike because of the many metabolic advantages it offers.

As Mark Sisson, bestselling author of The Primal Blueprint explains, ”Fat adaptation is the normal, preferred metabolic state of the human animal. It’s nothing special; it’s just how we’re meant to be.”

Fat adaption provides the body with metabolic flexibility; it allows the body to burn both fats and carbohydrates--effortlessly switching between the two fuel sources, depending on its specific needs. The fat-adapted athlete will be able to empty her glycogen stores through intense exercise, then refill them; move on to burning whatever dietary fat hasn’t been stored, then easily access and utilize stored fat when that becomes necessary. 

Many active women have found that following a primal diet with its emphasis on eating what our hunter-gatherer ancestors ate (fewer carbohydrates, a moderate amount of protein, and an ample supply of healthy fat) has made a significant and positive difference in how they look, feel, and perform. In addition to feeling less hungry and enjoying more consistent energy throughout the day, those who follow an ancestral diet can benefit from its anti-inflammatory effects.

How do you know if your body is fat adapted? Ask yourself the following questions:

1. Does skipping a meal cause me to suffer from ravenous hunger, anxiety, headaches, and brain fog; or can I easily and comfortably go four to five hours without eating?

2. Do I experience peaks and valleys of energy that often leave me longing for a nap; or do I enjoy steady, even energy throughout the day?

3. Do I struggle to maintain a lean body composition; or am I relatively unconcerned about carrying excess body fat?

4. Do I need to eat something the minute I wake up; or can I do 30 to 45 minutes of low to medium intensity exercise in the morning before I eat?

If you answered “yes” to (the latter part of) all four of these questions, you are fat adapted and have achieved a state of metabolic flexibility that allows you to be a more adaptable eater. You might get a little hungry, but you won’t “crash and burn” if you happen to miss a meal. You can access and burn stored body fat when you need to, without consuming any carbohydrates. When you do have an ample supply of glucose (blood sugar), your body will be able to use that without becoming dependent on it.

If you answered “no” to most of these questions, it might be time to evaluate the composition of your meals and re-balance of your macronutrient intake. 

 How do you know what percentage of carbohydrates, fats, and proteins you should be eating?  

There are as many answers to this question as there are female athletes. While it requires patience and perseverance, a fair amount of personal experimentation will be necessary. Consider using a free app like Cronometer to keep a three or four day food log to get a baseline measurement of your current macronutrient intake totals before you start to make any adjustments.

As a very general recommendation, strive for a macronutrient balance that’s 20 to 30% complex carbohydrates, 30 to 40% high-quality protein, and 30 to 40% healthy fat (based on caloric intake, not portion size). Establishing some initial macronutrient targets will give you a direction to move in and, eventually, determine the ratio that’s right for you. 

 The end goal is to learn how you need to fuel your body with lasting and consistent energy.

When you achieve this goal, a lot of good things will begin to happen. From a metabolic standpoint, your blood sugar and insulin levels will remain low, keeping cortisol in check so you’ll feel calmer and enjoy more even energy. Since your body’s inflammatory and immune responses won’t be activated or depleted, you might have fewer aches and pains and get sick less often. If you do get injured or become ill, you may find that you bounce back quicker since all your energy resources can be fully mobilized and utilized for positive, productive, and regenerative purposes. Maintaining a lean body composition—regardless of your activity level—will probably require less attention and effort, too.

Feel good about sticking to the diet that works for you, regardless of what philosophy it resembles: low-carbohydrate, high-protein, low or high fat; Mediterranean, paleo, keto, or vegetarian. In many cases, these dietary schools of thought revolve around the central objective of weight loss. But the pursuit of optimal health, performance, and recovery is the bigger-picture priority. 

As you begin to create a long-term plan for optimizing your macronutrient balance, it’s helpful to establish and track few parameters so that you can have a sense of how any adjustments you make are impacting your health and recovery status. 

Here’s a short list of some variables you might want to consider tracking. Are you: 

• Falling asleep any easier?

• Sleeping more soundly?

• Feeling calmer?

• Having an easier time with digestion and elimination?

• Becoming more motivated to set goals and start new projects?

• Able to go four to five hours between meals without feeling hungry and/or experiencing changes in your energy, mood, or ability to concentrate?

Choose the parameters that are most relevant and meaningful to you, and make sure that they are measurable. Write down the number of times you wake at night, for example; or assess your energy or irritability on a scale from one to five. Allow your body a week or two to adapt to any major macronutrient changes you make before implementing any further adjustments.