9 Fitness & Diet Myths Women Believe: Survey Results (2023)

Our recent survey of 236 women uncovered what myths women believe about fitness and nutrition. 

The results show how misinformation can affect women across age and experience — even those who consider themselves well-informed when it comes to fitness.

Why is this important? 

Fitness myths can be more than just harmless misunderstandings; they can steer you off course, affecting your health and goals. 

Our study took a close look at 9 myths in women’s fitness, ranking them by how widely they’re believed. 

Key Takeaways

  • Widespread Myths Across Demographics: One of the most notable findings is how pervasive some myths are, cutting across age, income, and even exercise frequency. For instance, 62% of women believe that taking calcium supplements is essential for preventing osteoporosis, making it the most commonly believed myth in our survey.
  • Misinformation Among the “Well-Informed”: Women who consider themselves “very familiar” with fitness and nutrition concepts are often more likely to believe in these myths. This highlights the complexity and prevalence of misinformation in the fitness industry, suggesting that confidence doesn’t always correlate with accuracy.
  • Age-Specific Beliefs: While some myths are universally believed, others appear to be age-specific. For example, younger women are more likely to believe that extensive cardio is essential for weight loss, while women aged 55+ are more likely to view carbohydrates negatively. This underscores the need for targeted educational initiatives across different age groups.

Myth #1 – Women Need A Calcium Supplement To Prevent Osteoporosis 

Myth #1 - Women need a calcium supplement to prevent osteoporosis

62% of women believe that women need to take calcium supplements to prevent osteoporosis (a condition where bones become weak and brittle).

  • This is the most widely believed, with the highest percentage of women believing it (out of the 9 myths we tested).
  • This is the only myth where women who exercise 3+ times a week are equally misinformed as those who exercise less (63% vs 61% believe it). On all the other myths we tested, regularly exercising women are better informed.
  • Women who say they are ‘very familiar’ with nutrition and fitness concepts believe it more (71% believe it)
  • Women aged 35+ believe it more (65% believe it)
  • Women with higher household income (75k+ USD) believe it more (69% believe it vs 57% of those with lower income)

REALITY: Dietary calcium can slow or prevent the age-related loss of bone mineral density, but only slightly, and getting it from food is just as effective as using a supplement. However, neither one can prevent or cure osteoporosis.(1)(2)(3)

Myth #2 – Women Need Supplements Designed For Women Specifically

Myth #2 - Women need supplements designed for women specifically

52% of women believe that women need supplements designed for women, such as whey protein powders for women.

  • This is the topic with the highest uncertainty: 22% of women say they’re not sure what to believe
  • Women who exercise less than 3 times a week believe it more (56% vs 45% those who exercise 3+ times)
  • Women aged 35-54 yrs believe it most (56% of them believe it)

REALITY: Although energy (caloric) needs differ between men and women, they’re similar relative to body weight. Adult men and women also have similar vitamin and mineral needs, with the exception of some vitamins and minerals, like iron (women require about twice as much per day).(1)  The serving sizes and amounts of certain nutrients might differ — like a women’s product containing more iron or fewer calories per serving — but the ingredients themselves are the same regardless of the packaging.(2)

Myth #3 – Women Will Get Bulky From Lifting Weights 

Myth #3 - Women will get bulky from lifting weights

39% of women believe that over enough time women will get bulky from lifting weights.

  • This myth sees the biggest difference between regularly exercising women (28% of them believe it) and those who exercise less often (45% believe it)
  • This myth is particularly widespread among women with lower income: 41% of them (with household income 75K USD or below) believe it, vs only 33% of those with 75K+ USD income believe it
  • Those who claim to be ‘very familiar’ with nutrition and fitness concepts believe it more (54% believe it, vs only 33-40% of those who think they are less familiar or not at all familiar)

REALITY: It’s true that women can gain just as much — and sometimes more —  relative strength and muscle mass as men. In other words, a 20-week training program can increase someone’s leg press by 50% or bicep circumference by 2%, for example, regardless of gender.(1)(2) However, even with proper nutrition and a tough training plan, muscles grow slowly. At rates of just one to two pounds per month at best, it takes years to add noticeable muscle mass without the use of performance-enhancing drugs.(3)

Myth #4 – Eating Fat Makes You Fat

Myth #4 - Eating fat makes you fat

36% of women believe that eating fat makes you fat.

  • Women with lower income tend to believe it more (Under 75K USD: 40% vs Over 75k USD: 30% believe it)
  • Women over 55 yrs are better informed: only 29% of them believe it (compared to 39% in the younger age groups)

REALITY: Body fat is gained when a person eats more calories than they need, regardless of whether those calories come from fat, carbohydrates or protein. Dietary fat has more calories per gram than carbohydrates or protein, so it can be easy to take in a lot of calories from small servings of high-fat foods, like peanut butter or olive oil, compared to lower-fat foods like fruit. However, dietary fat intake doesn’t cause fat gain when a person’s caloric intake matches their calorie needs.(1)

Myth #5 – Carbohydrates Are Bad

Myth #5 - Carbohydrates are bad

32% of women believe that carbohydrates are bad for you.

  • Those who exercise 3+ times believe more than carbs are actually good for you (54% vs 44% amongst those who exercise less)
  • Women over 55 yrs tend to believe it more: 37% of them believe it (compared to 30% in the younger age groups)
  • Women under-35 are the best informed: 56% believe that carbs are generally good for them (vs only 44% say that amongst older women)

REALITY: Not all carbohydrates are the same. Complex carbohydrates are found in a number of health-promoting foods, including fruits, starchy vegetables, beans and whole grains. Whole grains are linked to lower risks of type 2 diabetes, colorectal cancer, cardiovascular disease and prostate cancer.(1) Eating several servings of fruits, vegetables and beans each day can reduce the risk of dying from cardiovascular disease.(2) However, foods with refined carbs and added sugars — like soda, candy and pastries — are linked to cardiovascular disease and stroke risk, so it’s recommended to limit added sugars to 25 grams per day.(3)

Myth #6 – Women Need To Do Lots of Cardio To Lose Weight

Myth #6 - Women need to do lots of cardio to lose weight

32% of women believe that you need to do lots of cardio to lose weight.

  • This myth is the most age-dependent and misbelief decreases with age: 42% of women under 35 yrs believe it, 35% of those aged 35-54 yrs and only 22% of those aged 55+.
  • Those who exercise regularly are better informed (64% do NOT believe it vs 51% among those who exercise less)
  • Women with lower income tend to believe it more (Under 75K USD: 37% vs Over 75K USD: 24% believe it)

REALITY:  Cardio can be a great way to improve your cardiovascular health, and it can support weight loss goals when combined with a modest calorie deficit, but you don’t need to spend hours in the gym. Studies show that, in addition to reducing calories, performing 150 to 250 minutes per week of moderate-intensity cardio can produce significant weight loss.(1)(2) Contrary to popular belief, doing longer bouts of cardio while following a very low-calorie diet isn’t as effective for most people. In fact, it’s fairly common for people to unknowingly compensate for long cardio sessions by moving less for the rest of the day, especially when they’re beginning to exercise regularly.(3)(4) So, even though they’ve started exercising, their total energy expenditure isn’t that much higher. For weight loss, it’s best to do 30 to 50 minutes of moderate-intensity cardio three to five days per week while reducing calories by 350 to 500 per day. It’s also worth noting that, although performing 150 to 250 minutes of moderate aerobic activity per week can prevent weight gain, it isn’t very effective on its own for weight loss.(1)(2)  

Myth #7 – Pregnant Women Should Avoid Exercise

Myth #7 - Pregnant women should avoid exercise

12% of women believe that pregnant women should avoid exercise.

  • This myth is not widespread, only 12% believe it and 80% explicitly say they don’t believe it.
  • Still, those who think they are ‘very familiar’ with nutrition and fitness concepts are the most likely to believe it (25% of them).

REALITY: For the majority of women with healthy pregnancies, exercise — including vigorous exercise and resistance training —  is both safe and beneficial for the duration of the pregnancy. It can reduce the risk of developing gestational diabetes, improve sleep quality, reduce fatigue, and support normal weight gain during pregnancy. It may also prevent hypertensive disorders in some women.(1)(2)(3)(4)(5)(6)(7)(8)

Myth #8 – Women Should Avoid Exercise While Menstruating

Myth #8 - Women should avoid exercise while menstruating

12% of women believe that women who are menstruating should avoid exercise.

  • Women are best informed about this topic. 83% of women explicitly know it is not true.
  • Women who exercise 3+ times a week are particularly well informed (93% say they don’t believe it vs 78% who exercise less)
  • Being well-informed increases with age: 91% of women aged 55+ don’t believe it vs 83% of women aged 35-54 yrs and 75% of women under 35.

REALITY: Overall, menstrual cycle phases appear to have little to no effect on strength or aerobic exercise performance. Some studies show that women might notice reduced performance or need more recovery time in the first or last few days of their period, but there’s no evidence that women should avoid exercise while menstruating.(1)(2)(3)(4)

Myth #9 – Women Shouldn’t Eat Carbs During Their Period

Myth #9 - Women shouldn’t eat carbs during their period

8% of women believe that women shouldn’t eat carbohydrates during their period.

  • There is only a little misinformation about this topic (8%), but there is a rather high level (19%) of uncertainty, too.
  • Women who exercise regularly are better informed (81% don’t believe it vs 68% among those who exercise less)
  • Being well-informed increases with age: 79% of women aged 55+ don’t believe it vs 73% of women aged 35-54 yrs and 65% of women under 35.

REALITY: There’s some evidence that women notice a bigger appetite and stronger cravings for sweet or salty, high-carb, high-fat foods in the days before their period, but there’s no evidence that they should be avoided during menstruation.(1)(2) Some studies show that women rely slightly less on carbohydrates (and more on fats) for energy during exercise while menstruating, but others indicate that there’s no difference. Either way, these changes don’t affect exercise performance.(3)(4)(5)(6)(7)(8) According to the International Society of Sports Nutrition, women should eat enough carbohydrates across their menstrual cycle phases to meet their energy needs.(9)


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About The Author

Avi Silverberg

Avi Silverberg is an author, coach, and the Founder of FeastGood.com. Avi has a Master of Science in Exercise Science and has published over 400 articles on the topics of health, exercise, and nutrition.

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