The term carb cycling is thrown around a lot in the weight loss world, it’s a popular tool used by nutritionists and personal trainers to speed up weight loss. It’s a tool that I myself have tried and tested, and if used correctly and under the right conditions it really does work. Note the words correctly and right conditions….

How carb cycling works

Your week is divided among three types of days: no carb days, low-carb days and high-carb days. The theory goes, carb cycling manipulates insulin to minimize fat storage and maximize muscle synthesis. Low-carb and no-carb days help us to become more insulin sensitive, and promote fat burning. While high-carb days help to maximize muscle growth and replenish carb storage that enhances exercise intensity.

As I mentioned above, I have seen it firsthand and carb cycling is a genuine, effective tool for fitness and weight loss when used correctly. The problem is when it’s not used correctly it can play havoc with a women’s delicate hormonal system. Carbohydrates are an important part of a women’s diet especially if there are thyroid issues, mood issues, HPA axis dysregulation and hypothalamic amenorrhea. They are also very important in pregnancy, nursing and conception.

If you are a woman and you want to give carb cyling a go, there are three important considerations to bear in mind:

Make sure you protect your thyroid

Thyroid hormone is essential for fat loss. Unfortunately, on a low carbohydrate diet thyroid hormone production can slow down – leading to your thyroid hormones not being produced in the proper proportions. This seems to be more of a problem for women as their metabolism and thyroid activity is much more sensitive than men’s. Incorrect proportions of thyroid hormones cause all the symptoms of hypothyroidism- something we all want to avoid.

What can you do?

Make sure that on the “low carb” times of the cycle you are still not eating very very low carb, stay above 50 grams of carbohydrate a day, at the very least (and higher if you are very active).

Examples of 50g of carbs are:

  • 1 large sweet potato and 1/2 a cup of blueberries
  • 1 cup of butternut squash and a pear
  • 1 cup of sliced plantain
  • 1 cup of rice and a plum


Synchronize your carb cycling with your menstrual cycle

Estrogen and progesterone have an important impact on carbohydrate metabolism. Estrogen slightly increases, and progesterone decreases insulin sensitivity. During the follicualre phase (the first two weeks of the cycle) carbohydrates are processed much more efficiently, whereas during the luteal phase (after ovulation, in the last two weeks of the cycle) ) carbohydrates are processed with much more fat storage.

Stay away from starvation mode

Whist carb cycling you also need to make sure that you are consuming enough calories. Women seem to think the lower the calories the more effective the diet. If you’re not consuming enough calories and going too low in carbohydrates to support activity, you could be messing with leptin’s ability to regulate your reproductive hormones. By going too low in both carbs and calories, you can also send signals to your body indicating that it is under stress. Whilst under stress your body is not in baby making mode, it is not prioritizing a baby if it is worried about its next meal. This is when you see amenorrhea or fertility issues. If you are trying to conceive, it is important to remember being in a fed state is critical for convincing the body it is in a healthy enough environment to make babies.

Take home message

Carb cycling is a good piece of kit if used correctly, and responsibly. Instead of sticking to a simple regimen provided by a PT or some internet forum, be mindful and work with your female body. Remember you do not have to follow it to a tee to reap the rewards; the key is keeping those delicate hormones of yours in check, not starving yourself or going very very low carb. With a few adjustments, patience and room for adjustments, it can be used efectively to keep unwanted insulin weight off.

Work with Emma-Louise

Interested in receiving one-on-one support? I currently work with a select number of clients each month interested in nutritional therapy.