Why Women Aren’t Small Men: Nutrition for the Female Body

Have you ever followed the same nutrition plan as your boyfriend, husband, trainer, or even your brother and thought, "Why am I not getting the same results?" You're not alone, and it's not your fault.

For decades, almost all health, fitness and nutrition research has been conducted solely on men. The outcome? Women have been handed dietary advice that doesn’t reflect our unique biology. As Dr. Stacy Sims famously says, "Women are not small men."

We're hormonally, metabolically and structurally different. It only makes sense that our nutrition and exercise should reflect those differences. Let’s first unpack how our different hormones influences energy, metabolism and exercise, and what you can do to work with your body, not against it.

Hormones 101

Women are biologically wired to protect reproduction. When energy is too low, particularly carbohydrate availability, this triggers a suppression of a key reproductive neurons called kisspeptin, which can disrupt your cycle, reduce estrogen, slow metabolism, and impair bone health. Men also experience kisspeptin suppression but only in severe energy deficits. Women? We're more sensitive and it can happen fast.

This is why men often see results from simply exercising more and eating less. For women, however, this approach is far less effective - we need to be more strategic and intentional with both the quantity and timing of our nutrition. Since exercise is a physical stressor, under-fuelling, especially around high-intensity sessions, can amplify hormonal disruption.

Additionally, while men function on a short steady 24-hour hormonal clock dominated by testosterone, women operate on a more complex monthly cycle that affects nearly every aspect of our health: from energy and mood, to hunger and muscle recovery. 

The result? Strategies like intermittent fasting, fasted training, or strict calorie cutting might work for men, but they often backfire for women. Now, let’s break down your cycle and what your body needs in each phase.

 

Follicular Phase (Day 1–14): Time to Push Hard

This phase starts with your period and lasts until ovulation. Estrogen levels gradually rise, helping you feel more energetic, focused, and resilient. Estrogen also boosts insulin sensitivity and helps regulate cortisol, our main stress hormone. This is a perfect time to increase your intake of quality carbohydrates. With motivation to train and tackle big tasks running high, your body needs the right fuel to support both brain and muscle function. As exercise intensity (which is a form of stress) increases, your body relies even more on carbs to support cortisol regulation, preserve reproductive hormone function, and prevent energy shortfalls that can disrupt your cycle. So if your last main meal was a while ago or its first thing in the morning, grab yourself a small, carb-rich snack before training like a banana or a couple of dates - this is essential to fuel performance, protect hormones, and support recovery.

To supercharge your workout, pair your snack with the Nu Harvest Pre-Workout (the only pre-workout I use) for a natural, energising, hormone-friendly session.

Luteal Phase (Day 14–28): Time to Nourish and Recover

After ovulation, progesterone takes the spotlight. This hormone is essential for preparing the body for a potential pregnancy, but it also raises your core body temperature, increases your metabolic rate, and can make you feel more bloated and tired. You might notice disrupted sleep (Hello Moon Mylk), increased cravings, or a general sense of being "off." Your stress tolerance also drops, as cortisol and progesterone compete for resources. However, we can mitigate this and still perform well physically and mentally if we support our body with slightly more food, especially protein! This helps prevent muscle breakdown, stabilise energy, increase satiety and support hormone balance.

An easy win? Sip Nu Harvest Protein Water throughout the day to boost protein intake and hydration and/or add in an extra high protein snack like one of the Nu Harvest bake mixes to stay satisfied and strong.

GIRLS! Stop Skipping Breakfast (Especially Before Exercise)

Let’s paint a picture: It’s 5:30AM, you’re hitting a workout fuelled only by coffee, rushing home to get ready, and by 9AM you’re deep in emails and meetings with no proper food in sight. Sound familiar?

You may feel wired but tired, struggle with gut issues or skin flare-ups, and notice your workouts aren’t really working. You’re likely running on high cortisol. 

For men, cortisol rises in the morning and naturally tapers. But for women, skipping breakfast means cortisol keeps climbing. Chronically high cortisol can:

• Dysregulate blood sugar
• Increase inflammation
• Suppress progesterone (hormone harmony killer)
• Encourage fat storage (especially around the belly)
• Impair muscle repair and energy burning capacity

There's a key physiological difference: men have more efficient glycolytic systems, meaning they can better tap into stored muscle carbohydrates during fasted workouts. Women's bodies, however, function differently. When women train fasted, it can prompt the release of cortisol to elevate blood sugar for fuel, which may result in breaking down valuable muscle tissue known as proteolysis (unfortunately no - you don’t just simply burn fat) to complete the session. So, if you frequently skip breakfast or exercise with limited carbohydrates, your cortisol levels will likely be high. 

 

Solution? Eat breakfast ideally within 1 hour of waking up and ALWAYS fuel your workouts! 

While you may not want to hear it, your gut functions much like a muscle - it can be trained to tolerate early meals or meals closer to exercise if that's currently a challenge. Begin with small steps:

• Pre-workout: Personally, I like to batch-make a week's worth of protein energy balls using just five simple ingredients: Nu Harvest Protein, oats, honey, almond butter, and a pinch of Celtic salt. Quick, fuss-free, and easy to digest. 
• On the go? Liquid options are often easier to tolerate, especially in the morning. Grab a Nu Harvest Busy Gal Shake to help keep cortisol in check and fuel your day. As your appetite picks up, try prepping something more substantial like protein overnight oats with chia seeds and fruit for a quick, nourishing upgrade. 
• Need caffeine first thing? Skip the coffee and switch to Nu Harvest Matcha. It gives a slower release of caffeine, supporting sustained energy without spiking cortisol. Mix it with soy milk for extra carbs and grab a banana to make it pre-workout fuel. 

Fuel first = lower cortisol, better performance, and stronger hormone health.

 

My Story: Why This Matters So Much

As a dietitian, I help women develop sustainable eating habits that work with their bodies. But I wasn’t always in tune with my own.

Years ago, I was training hard, fasting, and trying to "save" calories. Despite being an elite athlete, I felt constantly hungry, craved sugar, couldn’t progress in training, and eventually lost my period. This triggered a domino effect: hormonal disturbances, gut issues, persistent acne, and complete burnout.

Frustrated by a lack of answers, I turned to nutrition science. Through study and personal trial and error, I realised how deeply misunderstood women’s bodies are in mainstream health advice.

That experience lit a fire in me to make sure other women don’t go through the same.

Final Note:

Understanding your unique body starts with tracking your cycle to identify personal patterns in energy, mood, and other related symptoms. And for any of you reading this who are currently using the oral contraceptive or dealing with irregular or absent periods because of PCOS or hypothalamic amenorrhea, my strong advice is to book an appointment with a functional dietitian specialising in women's health, because your nutritional needs will require more tailored guidance.

You are not broken. You just haven’t been given the tools to work with your physiology.

If you’re ready to start fuelling your body in a way that actually supports your hormones, energy and recovery, Nu Harvest has you covered. Whether it's matcha, protein water or Busy Gal Shakes, the entire NH range has been designed with women’s bodies and unique needs in mind.

Use my code KYAHENGLISH at checkout for 15% off - because you deserve products that work with your body, not against it.