Dr Susan Baxter
Females vs males … Intermittent fasting
Updated: Mar 2
Intermittent fasting or IF has a plethora of different potential protocols to follow, but overall the message is the same: there are parts of the day (or sometimes a whole day) where no food is consumed. It limits when you are allowed to eat. It has been suggested as a good weight loss strategy (essentially restricting your ability to eat whenever you want). Some advocates believe that it makes them stronger in sessions, others that it is a miracle weight loss strategy.
Here are my 2 cents. For males and females, regardless of what you eat, you spike your blood sugar level and insulin response (unless you have a problem with this system). Whether you eat carbs or protein, you will experience this response. Some foods create a greater spike over a shorter period of time (those with a high Glycemic index). If the glycemic index is lower, then there is a smaller spike but over a longer period of time.
These spikes can trigger fat storage, simply because you are consuming energy and your body isn’t relying on the available sources of energy.
Advocates of IF believe that by reducing the number of these spikes over the course of the day, by eating less frequently, you are less likely to be storing fat. Which would make sense. Therefore they eat less frequently in certain windows.
However, eating a larger meal less frequently than small meals more frequently would only provide a metabolic advantage if there was the same ’spike’ regardless of meal size. In actual fact, the spike is greater for a larger portion, and therefore the advantage of a larger meal over a couple of smaller meals official overall size would not have any advantage than perhaps less opportunity to overeat (because each time you eat, you open yourself up for a greater chance that you might overeat).
BUT for females, there is an extra level of consideration that should apply. Females might not benefit quite as much as males by following intermittent fasting. The reason is that females have different hormones and genetic make up.
That is not to say that IF is a no no for females (it has worked for many, and if it works for you, definitely do!).
However the idea that it is the new miracle diet is incorrect, especially if you read this research.
Now before you point out that it is on rats and not humans: much scientific research has to be done on rats since you cannot ethically restrict and control all factors of someone's diet as much as you can for rats. It’s extremely hard to recruit people and completely control for their fitness level, experience, and upbringing, never mind convince them to be in a controlled environment for 6 weeks and only eat exactly what you allocate them.
The results of the study indicate that there was actually a poor effect on the reproductive health of the female rats that did IF. Their hunger hormone was also greatly increased.
That matters because the female hormone system and metabolism have extreme overlap. Estrogen’s are your body’s metabolic regulators. If you do something that causes your estrogen to drop, you could find yourself feeling a lot hungrier with increased appetite.
Estrogens modify the peptides that signal you to feel full (cholecystokinin) or hungry (ghrelin). In the hypothalamus, estrogens also stimulate neurons that halt production of appetite-regulating peptides.
Therefore if you do something that affects this balance of estrogens (as intermittent fasting was shown to in this article), you could actually have the opposite effect that you desire (which would be greater health I presume?).
So what does that mean for you? Like I said if it works for you, do it! I am also trying to indicate that it might not be for everyone, and could be dangerous.
Signs not to ignore:
Missed menstrual cycles
Less sexual interest
Sleep problems (Check my post on sleep and gains)
inability to cope with stress
(There are more of course)
If you like what you read, I do have a series of Ebooks you can find here. I have designed these to inform and educate with real no-nonsense information about how to live a sustainably healthy life long term. It is the tool kit and knowledge that you need to make your own informed decisions for long-term health.
Thank you for reading.