Intermittent Fasting for Women Over 40

Are you a woman over 40 and looking to lose weight with an intermittent fasting diet? It’s natural to gain weight once you hit your 40s due to hormonal and metabolic changes, and intermittent fasting can possibly reverse this.

Intermittent fasting is a scientifically proven dieting method that can enhance weight, improve longevity, and boost overall health. But are there any differences with intermittent fasting when you’re a woman over 40?

Women over 40 can quickly have weight loss using intermittent fasting when done correctly. It can help reduce calorie intake, improve hormones, and boost metabolism. But many women in their 40s and 50s end up making serious mistakes with intermittent fasting that stop their results.

Here you’ll uncover how women over 40 can effectively use intermittent fasting to get results fast and prevent the many common mistakes that can keep you from succeeding with this dieting method.

Is Intermittent Fasting Good for Women After 40

perimenopausal woman intermittent fasting

Intermittent fasting is alternating between periods of eating and not eating. Your body isn’t designed to be eating around the clock and can benefit from taking extended breaks from eating.

Throughout human history, we didn’t use to have access to food all the time like we do today with the refrigerator and pantry nearby. So our bodies evolved to survive longer by holding onto fat stores for a future famine.

So by cycling between periods of eating and not eating, you’ll allow your body to tap into fat stores for fuel. This will force you to lose weight since you’ll reduce your calorie intake while burning fat stores.

Your health will also benefit by:

  • improving hormones
  • speeding up your metabolism
  • strengthening gut health
  • enhancing longevity

But females in their 40s and those who are perimenopausal need to approach intermittent fasting differently. When done correctly, intermittent fasting can be good for women’s hormones, but it could also be bad when done the wrong way.

Pregnant or breastfeeding women are not advised to do intermittent fasting because they need to have a high amount of nutrients and low stress during this time.1 Pregnant or breastfeeding women also need higher calories to provide for themselves and the baby.

How Should a 40-Year-Old Woman Fast?

restrict calories hunger hormones woman over 40

When women enter their 40s, they can begin to enter perimenopause too. With perimenopause, the hormone progesterone begins to decrease while estrogen increases.2 Studies have found that the average weight gain from perimenopause can be 11 to over 20 pounds.3

Estrogen has been found to promote fat buildup in the body, especially the belly.4 Less progesterone in the body also reduces fat burning, making it easier to gain weight.5 With higher estrogen in the body, you’ll also become more prone to insulin resistance which too can contribute to weight gain.6

But the good news is intermittent fasting for women does work over 40. In some ways, intermittent fasting works better for females in their 40s since they have a more powerful response to catecholamine during intermittent fasting.

Catecholamines are neurotransmitters like adrenaline, norepinephrine, and dopamine that help to increase metabolism, burn fat, and reduce appetite. Intermittent fasting helps improve catecholamine response, but it’s even more profound for women in their 40s.7

How Many Hours Should a 40-Year-Old Woman Fast

intermittent fasting plans for women over 40

There are quite a few different types of common intermittent fasting methods. Many intermittent fasting schedules can get results, but the one that would be most successful for a 40 old woman will be different from a 20 year old man.

The best intermittent fasting for women in their 40s is generally on the lower end of fasting windows. Shorter fasting periods with a larger eating window will still produce weight loss while preserving muscle mass and making it easier to stick with. Extended intermittent fasting for long periods of time consistently can stress the body of a 40 year old woman too much.

If your body becomes too stressed from extended intermittent fasting, it could cause hormonal belly fat by producing too much cortisol, promoting weight gain.8 If you’re used to eating throughout the day, you could get low blood sugar and fatigue as your body gradually becomes fat-adapted instead of being a “sugar burner.”

So it’s best to start off on the lower end of intermittent fasting windows with 12 to 14 hours to start. From there, you can gradually work up to 16 to 20 hours of fasting daily. But with intermittent fasting for women, it’s not always the best idea to do it every day of the week. 

Best Intermittent Fasting for 40-Year-Old Woman

eat healthy foods with intermittent fasting

A 16 to 20-hour fast for 2 to 4 times per week is usually the right schedule with intermittent fasting for women. Fasting too long too much can mess up your luteinizing hormone pulses.9 This can catapult you into menopause even faster, which many women wouldn’t want to happen.

The best time for women to fast is during the follicular phase of your cycle when estrogen is highest. Estrogen makes you feel more satiated and will help to make you feel fuller for a longer time.10 Then in the luteal phase of your cycle, progesterone is elevated, making you hungrier and much harder to stick with your fasting schedule.11

Try to eat more fiber and soluble fiber before starting your fasting window. More soluble fiber (prebiotics) will help to support your gut microbiome. Estrobolome are your gut microbial genes that can metabolize estrogens.12 To better keep your estrogen levels balanced, it’s best to make sure your gut health is good.

Fasting for 20 to 24 hours can be done, but it’s not recommended to do it continuously because it can be too stressful for your body. If you build up to a 24-hour fast, it’s best to limit it to 2 to 3 times per week. Alternate-day fasting over 40 can also be done, but it’s recommended not to do it continuously.

And these guidelines can differ, depending on the person and how well your body is adapted to fasting. Some can go for longer fast more often, while others must reduce the frequency and length of fasting periods.

How Can a 40-Year-Old Woman Lose Weight Fast

If you want to know how long it takes for intermittent fasting for women over 40 to work, then the good news is you’ll start seeing weight loss within a week. You should be getting results as long as you’re sticking to your fasting schedule and eating a balanced low-carb diet the rest of the time.

It can be challenging for women over 40 to lose weight because of hormonal fluctuations and metabolism shifts.13 Lifestyle changes also make it hard to gain weight due to sedentary activity, lack of exercise, poor diet, bad sleep, and high stress. Practicing intermittent fasting combined with a healthy eating plan can reduce chronic inflammation, improve insulin resistance, and reduce body fat.14,15

But if you stick with an intermittent fasting schedule, then you could expect to lose at least 10 pounds in your first month. If you’re not losing weight on intermittent fasting, you could be retaining water weight. You’ll hold water weight up to 10 days before your period.

It’s best to combine intermittent fasting and a low-carb diet. You don’t have to go full ketogenic diet, but it helps a lot to avoid sugars, refined grains, and processed foods. Limit your calories, eat high protein foods, dark green leafy and cruciferous vegetables, healthy fats, and some low-sugar fruits.

Working out while fasting can also help produce better results since your body will be forced to burn fat stores for exercise fuel. Muscle mass will help to improve body composition while enhancing weight loss.16 Even going for a walk while fasting can boost weight loss.

Add some fasting drinks or C8-MCTs to trigger the “metabolic switch” and jumpstart fat burning.

My Pick
BioTrust Keto Elevate

Support Many of the Keto Benefits Associated With Increased Ketones, & Support Them FAST, but Without the Difficulty of Doing Keto...

Increase Ketone Levels Inside Your Body to Boost Metabolism, Elevate Energy & Enhance Mental Focus

  • 3X Better Than Coconut Oil, Butter or MCTs
  • Heightened energy levels
  • Reduced cravings & appetite
  • Graceful aging
  • Healthy metabolism
  • Increased mental clarity & focus
  • Heightened physical performance and recovery


Intermittent fasting is an effective weight loss strategy for women over 40. When done correctly, intermittent fasting for women enables the body to tap into its fat reserves for energy, promoting weight loss. However, it’s important to remember that the best intermittent fasting schedule may differ from what works for a younger person due to hormonal changes and other factors.

As progesterone levels decrease and estrogen levels rise, women in their 40s become more susceptible to weight gain and insulin resistance. The good news is that intermittent fasting can help combat these issues, as the increased catecholamine response during fasting boosts metabolism and fat burning, making intermittent fasting potentially more effective for women in their 40s.

Women in their 40s should start with shorter fasts of 12-14 hours per day, gradually increasing to 16-20 hours if desired. Fasting for 16-20 hours, 2-4 times per week, is optimal for women in this age group. Combining intermittent fasting with a low-carb diet and exercise can help maximize results while minimizing stress on the body.

With the right lifestyle changes, such as getting good sleep, reducing stress, and maintaining a healthy diet, women over 40 can expect to lose around 10 pounds within the first month of intermittent fasting.