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  • Writer's pictureTania Cucciniello

Why Keto & Intermittent Fasting are Different for Women

Yesterday was International Women’s Day and today I want to focus on these two very popular diets and how they are different for women. First, let’s look at what is a Keto diet and what is Intermittent Fasting (I.F).


A Keto or ketogenic diet is a low-carbohydrate diet which reduces body weight by controlling glycogen levels in the body. This diet favors good fats, like omega 3’s and 6’s, high protein, lots of vegetables but very little to no fruit at all, as fruit gets digested as a carbohydrate. This diet allows the body to burn fat from fat, rather than from carbohydrates.

Despite the benefits, such as lowering blood sugar, weight loss, fat loss, and increased energy; there is lack of evidence related to long-term safety of following this diet, especially for women. Low-carb diets may be effective in the short-term, but more research is needed to assess the long-term effects of this diet.


Intermittent Fasting is a method used to schedule when to eat and when to fast. The variety of fasting schedules and patterns are extensive, with the most popular method being the 16:8 ratio, where you have an 8-hour window to eat (healthy!) followed by 16 hours of fasting.

Additionally, I.F can be practiced with Carb-Cycling making this method known as the Intermittent Fasting Carb Cycle (I.F.C.C) diet. This method uses the eating “windows” in conjunction with cycling your carbs from low to high throughout the week. A typical carb-cycle includes 3 low-carb days, 3 moderate-carb days and 1 high-carb day, which must be within the feeding window. This I.F.C.C diet is the type of intermittent fasting we will be focusing on.

Cons of a low-carb diet

Without the proper introduction to these methods, fasting and low carb diets usually lead to cravings, which may also lead to an increase in stress and cortisol because now we’re fighting to control when and what we eat. Then, when the eating window opens, two common side effects are binge eating and eating to satisfy cravings, rather than eating a balanced meal of vegetables, grains, and proteins.

As mentioned above, these low-carb diets may be effective in weight control and glycemic control, but what happens in the long-term when glucose does not get replenished in the body?

Insufficient glucose levels in the body can lead to insufficient supply to the Central Nervous System (CNS), in which the CNS must find an alternative energy source, such as ketones, thus the keto diet benefits kick in. However, this option is not sustainable as the CNS will continue searching for energy only carbohydrates can produce.

Low glucose levels also increase uric acid concentration, which increases acidity levels in the body. This can lead to increased risk of developing kidney stones and stressing the liver. The liver then can't directly detect blood glucose levels; so, if there is a shortage of insulin, it assumes the body needs more glucose, sending its glucose stores back into the blood. This is not what Keto and I.F.C.C diets need the body to do when eating high levels of fat and protein.

Furthermore, the pancreas might not perform at optimal levels as certain enzymes only get produced when eating carbohydrates, specifically amylase. Amylase is a pancreatic enzyme, activated by saliva while chewing, that helps break down starches into sugar and then your body uses this for energy. However, the less carbs you eat, the less this natural process in the body occurs.

What also happens when you eat less carbs, is that glucose rarely gets converted into glycogen to be stored for energy later, increasing the risk of glycogen levels depleting. When there is no “gas in the tank”, so to speak, but you still must exercise, go to work, cook, clean and go about your day; your body runs out of “fuel” and fatigue sets in. Now, with no glucose in the blood stream and no back up storage of glycogen, the adrenals must push harder to produce adrenaline, that normally would have come from eating complex carbohydrates (not to be confused with refined/white carbohydrates).

Cons of a low-carb diet during exercise

At this moment, we can see that keeping carbs too low for too long can have detrimental effects on the body. Let’s add in the lifestyle of those who exercise, workout or train hard, such as athletes, personal trainers or yogis who practice every day, and we can see that they need much more energy to expend for performance. However, once again, if there is not enough glucose in the body, the body turns to fat and lean muscle for fuel, which means it’s eating at your gains. This compromises performance and endurance, decreases strength, causing the athlete or exerciser to hit a wall. Even with a high-fat pre-workout meal, fat takes longer to convert into energy compared to glucose, therefore the energy may not fuel the athlete when needed.

Likewise, that’s why one must never train or exercise on an empty stomach, so please make sure you exercise during the feeding window and not while fasted, as there is really no fuel to support these kinds of activity.

Bottom line, high muscle glycogen means increased capability to train longer. Carbohydrates are an optimal nutrition source pre-workout and encouraged in the post-workout recovery meal. To replenish glycogen stores, carbs and protein should be consumed within 30 – 60 minutes after exercise. This enables a faster return to training and supports repetitive training. Also, considering that it takes up to 20 hours to fully restore glycogen levels in the body WITH carbohydrates, imagine someone who is following a strict keto diet; those stores never replete. On this wise, if you are following a keto diet and you train, then consider ingesting the proper carbs right after a workout for speedy refueling. This is why even the most popular keto advocates on social media are also now saying to eat carbs sometimes!

Harmful side effects especially for women

All the cons listed above apply for both men and women. Now taking all this information above, on how low carbs can cause an increase of acidity levels, the liver to become stressed, the pancreas to decrease in function and exercise to become harder, plus let’s add female hormones; and we can get what is known as hypothalamic amenorrhea.

The hypothalamic area in the brain is responsible for producing hormones of LH, FSH, estrogen, progesterone, and testosterone. This tells the body how to regulate stress, digestion, energy, mood, and libido.

Amenorrhea is the phenomenon of when menstruation is absent during the reproductive years. It does not mean that the woman is infertile, but a stopped menstrual cycle does pose risks for hormone health.

Since low-carb diets can significantly disrupt hormone production, women with low carb intakes, especially athletic and active women, can face hypothalamic amenorrhea. This means the lack of carbs is cutting the signal to the hypothalamus, which is disrupting the menstrual cycle.

The best way to regulate an irregular or stopped period is, you guessed it, eat carbs again! Start reintroducing complex carbs back into your diet in small amounts every day to avoid bloating or weight gain. The reintroduction of carbs is just as important as the type of carbs you eat.

In my experience, if carbs alone don’t help your menstrual cycle, the next best way to regulate your period can be through taking natural supplements. Natural supplements are highly concentrated herbs and roots that gives the brain and the body a boost in the signals and functions it was lacking. The best supplements to help hypothalamic amenorrhea are Maca and Ashwagandha.

The benefits of both supplements are:

  • Decreases stress and cortisol- this helps the signal to the hypothalamus

  • Boosts brain function

  • Stimulates hormone production

  • Boosts fertility (in women and men)

  • Regulates bloating- especially with cortisol levels decreased

  • Regulates blood sugar

Maca and/or Ashwagandha can be taken daily for at least one month to be effective, or until the desired effect of a normal menstrual cycle returns. From then on, allow an adequate amount of complex carbs into your routine every day to maintain a healthy flow.

Pros of a low-carb diet

Although this article focuses on the cons of low carbohydrate intake, that doesn’t mean there isn’t a time and place for these methods to be used. Carbohydrate control is most definitely recommended for those with too much glucose in the blood and unhealthy eating habits, such as those at risk for Type 2 diabetes, high cholesterol, heart disease, epilepsy and multiple sclerosis, as too many carbs can increase inflammation; not something the body needs when dealing with these dis-eases.

Therefore, a low-carb diet is recommended, but still on the short-term until the desired health results are achieved for the individual who is struggling from such conditions.

Once the low-carb method has gotten glucose levels under control, incremental reintroduction to carbs may be practiced. This brings us to our next and final point, refeeding.


Once the body has decreased from being at risk, or once the eating window opens from fasting, or maybe after this article you’re considering reintroducing carbs back into your diet, then the refeed is crucial.

At this moment, the carb-cycle method would be recommended, which again includes 3 low-carb days, 3 moderate-carb days, and if you haven’t been eating carbs lately, don’t even aim for the 1 high-carb day at the end of the week. Start small, don’t shock the body by eating french fries and junk food just because you’re allowed to eat carbs again. Let the body get used to identifying and digesting carbohydrates all over again, allow time for the organs to regain functions that come from carbs, and this will prevent weight gain when reintroducing carbs.

Also, please choose complex carbs only since they are high in nutrients, such as beans, rice, quinoa, fruit; and avoid refined carbs like white flour, sugar, soda, and processed snacks. This last statement is recommended by ALL healthy eating guidelines and methods.


Once again, low-carb diets are proven to be beneficial in the short-term to achieve a desired effect such as weight loss and regulating blood sugar, however it is not a sustainable way of living, which means the body cannot support it for a long period of time. Only certain hormones or enzymes get produced through carbs, and this same statement can be said for protein and fats. Therefore, the best practice is that of all macros in moderation and portion control, as seen below.

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