Gender and weight loss
Things that may help men lose weight often don’t work, or can backfire, for women. Here are nine things to consider according to exercise physiologist and nutrition scientist Dr. Stacy Sims.
‘Women are not small men.’ This is the mantra of Dr. Stacy Sims, an exercise physiologist, nutrition scientist, and expert in female-specific training and nutrition for health, performance, and longevity. Known for her work in challenging the male-based research models in exercise science, Stacy repeatedly highlights, through numerous media interviews and in her books, that fitness and nutrition research is male-centric and ignores women’s unique physiology. Much of this advice not only doesn’t apply to women, but can have the opposite of the desired effect.
The author of the books ROAR and Next Level, Stacy focuses on sex-specific strategies for women’s health, training, and nutrition across puberty, perimenopause, and menopause. She also serves on the faculty at Stanford and Auckland University of Technology, and works with elite athletes and other active women. In this article, we summarise nine of the key points Stacy makes about the flaws and fallacies in mainstream health and weight-loss advice, as it relates to women.
1. Skipping breakfast or waiting too long to eat: Surviving on just black coffee until lunchtime? Women’s cortisol peaks early; delaying eating can prolong stress and trigger fat storage mechanisms. Eating something (even very light) within 30 minutes to an hour of waking helps to normalise stress hormone responses.
2. Training or exercising in a fasted state (especially in the morning): Fasted workouts can elevate cortisol and trigger muscle breakdown in women. Stacy encourages a small pre-exercise fuel, such as protein with some carbs, to blunt the stress response and protect lean mass. Her morning ‘proffee’ or protein coffee, has trended on social media.
3. Intermittent Fasting (IF): While men may benefit, for women, especially menopausal, prolonged fasts cause heightened cortisol, suppressed thyroid function, reduced metabolic rate, and disrupted hypothalamic signalling, which often leads to fat gain rather than loss, as well as muscle mass loss. Stacy says that extended fasting sends a stress signal to the hypothalamus, which impairs endocrine health and hinders weight loss.
4. Ketogenic diets: Like intermittent fasting, keto seems to calm men’s parasympathetic nervous system but has the opposite effect in women. Keto drives women’s stress response, raising anxiety, disrupting sleep, and derailing body composition.
5. Zone 2 training (low-to-moderate cardio): Spending hours jogging? While it’s popular, long, slow, low to moderate cardio (also known as Zone 2) isn’t ideal as a primary focus for women and was largely developed from male research. Stacy argues women benefit more from high intensity intervals for fat loss and metabolic health.
6. ‘Calories in, calories out’ restriction: The traditional model fails for women undergoing hormonal and metabolic changes, especially during menopause. Oestrogen decline alters how calories are processed, and women don’t respond to severe caloric deficits the same way men do.
7. Minimal or light resistance training: Traditional female-targeted routines, like light weights or high-rep toning, lack the stimulus needed for muscle and neural adaptation in menopausal women. Heavier loads (6–8 reps near failure) are needed to preserve lean mass and bone density.
8. Applying male-based protein guidelines: Women, especially older ones, need higher per-meal protein (around 30–35g post-exercise) and more overall daily protein for muscle synthesis. Male-based Recommended Daily Averages fall short.
9. Cold immersion (ice baths): Standard ice baths may be too intense for women and can hamper female muscle growth. Stacy recommends a milder cold (15–16°C) and avoiding cold immersion for at least eight hours post-strength training.
For more information, see drstacysims.com.
