Should I eat before exercise?
- Sophie Kane | APD, MDP
- May 21
- 3 min read
The Importance of Eating Before Exercise- Especially for Women
Fasted training or exercising on an empty stomach has been a popular among
people seeking to lose weight or “burn more fat”. But while the idea may seem
appealing as an easy solution, current evidence suggests that fasted exercise can
come with some big trade-offs- particularly when it comes to female physiology.
What Is Fasted Training?
Fasted training typically refers to exercising after an overnight fast, before
consuming any food. This is most common in early-morning workouts, where
individuals head straight into training without breakfast in an attempt to maximise fat
loss.
The rationale stems from the idea that, in a fasted state, the body will draw more
heavily on fat stores for energy. While it’s true that fat oxidation is slightly increased
during fasted exercise, this doesn’t necessarily equate to greater fat loss over time
(Schoenfeld & Aragon, 2014).
Let’s Unpack the Myth
More fat burned doesn’t equate to more fat lost. In reality, the body’s total calories
consumed versus expended is a stronger determinant of fat loss than whether a
workout is performed in a fasted or fed state. While fasted cardio may increase the
proportion of fat used during the session, studies show no significant difference in
body composition changes over time compared to fed workouts (Schoenfeld &
Aragon, 2014; Hackett & Hagstrom, 2020).
Furthermore, exercising without fuel may negatively affect performance, especially in
high-intensity or strength-based training, which rely more heavily on glycogen stores.
Reduced energy availability can compromise exercise intensity and training
adaptations and ultimately undermining the goal of improved fitness or fat loss.
Why Fasted Training May Not be the Best Choice
Women’s bodies are uniquely sensitive to energy availability, due to the complex
interplay between hormones, metabolism, and reproductive function.
As Dr. Stacy Sims, an exercise physiologist and researcher specialising in female
physiology, emphasises: “Women are not small men”- our hormonal environment
changes how we respond to training, stress, and fasting states.
Training in a fasted state can amplify physiological stress, potentially leading to:
Elevated cortisol levels, which in chronic excess may promote fat storage,
particularly in the abdominal region.
Disruptions in appetite hormones, including leptin and ghrelin, which may
increase cravings and overeating later in the day.
Impaired menstrual and reproductive function, particularly if low energy
availability becomes chronic.
Poor muscle recovery and protein breakdown, which can reduce lean mass
and training progress.
Low energy availability has been linked to a condition called Relative Energy
Deficiency in Sport (RED-S), which impacts not only reproductive health, but also
bone density, immune function, and cardiovascular health, again especially in active
women (Mountjoy et al., 2018).
The Benefits of Fuelling Before Exercise
Not feeling hungry first thing in the morning? That’s common- but even a light snack
with a good source of carbs and some protein can make a big difference, with key
benefits including:
Increased energy and stamina
Better mental focus and mood during exercise
Greater training intensity and output
Improved muscle protein synthesis when followed by post-workout nutrition
More stable blood glucose and reduced compensatory hunger later in the day
Examples of Pre-Workout Snacks to Try:
1 slice of toast with 1 tbsp peanut butter + ½ banana
Greek yogurt with fruit + honey
Oats with milk, ½ scoop protein powder + fruit
Smoothie with ½ banana + milk + ½ scoop protein powder
1 banana +1 boiled egg
Protein bar containing over 10g protein
Women thrive with nourishment, not deprivation and movement should support your
body, not stress it further. If you're unsure where to start, working with a dietitian can
help you create a routine that supports your goals without the confusion or
restriction.
Reach out to book a consultation or learn more about how we can support you.
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