Threw together some forum posts/replies to intermittent fasting related questions made in recent weeks, just to let you know that I’m still alive.

Had two clients competing this weekend, and they both placed very well, so keep your eyes peeled for the client update I’m going to put up later this week or next.


Q: “Do you think it is possible that breakfast is actually unhealthy for humans and we’re not wired for it?

When I was in elementary and middle school I never had breakfast, I didn’t have any instinct to eat at waking time. My siblings and parents ate their breakfast looking like zombies and after their breakfast they were even more lightheaded.

On the way to school I actually would begin to feel extremely good and concentrated. At school I never had problems following the lessons, taking notes, memorizing. I would skip recession eating as well. I have always noticed my classmates being less productive and more confused after their recession. I had high grades and school was easy for me.

Beginning high school I was pressured into having breakfast and eating something at recession. As I introduced breakfast in my nutrition I started to lose concentration in classroom, I was ravenously hungry at recession and my grades started to suffer. I was lightheaded the whole morning and couldn’t memorize things well.

After almost one year I was feeling worse the whole day (failing to make a connection with the addition of breakfast) I was so sick at the idea of eating one day that I skipped breakfast, and that morning I felt again good and concentrated in classroom. I finally decided to remove breakfast realizing that my instinct knew better than my doctor. I found out a lot of students who skip breakfast (consciously) feel a lot better and are a lot more productive and concentrated.

I have talked with people who keep telling me that if they have breakfast, a ravenous hunger is triggered the whole day and they would never stop eating. Yet if they follow their body lack of hunger in the morning, they never develop that hunger. Except for people who adapted by making an habit out of it, I don’t know anyone who naturally feel the need to eat at waking time. Most people, expecially middle school students, I talk to gets sick at the idea of eating in the morning.”

…I have always been told that at waking time our blood sugar are low and we need to eat. ” (original post shortened)

Answer: While I don’t necessarily think eating breakfast is ‘unhealthy’, it is certainly not a meal pattern we would be wired for from an evolutionary perspective. But then again, humans are highly adaptable and I’m not arguing that we should be clinging to what our ancestors did.

I can relate to some of the other things you’ve written, namely less alertness from consuming breakfast (and getting hungrier during classes). Some of my clients report better grades and motivation upon omitting breakfast as well.

Blood sugar is maintained within a very narrow range even during fasting. It never falls low enough to cause problems with attributes related to mental alertness unless you have a metabolic disorder (i.e diabetes) or raise insulin through exogenous means.

This was recently demonstrated in a study* using a wide variety of tests during a 48 hr time period, showing no detrimental effect of fasting (vs maintenance level calorie intake).

The authors of that study closes with the following

It should be noted that preservation of cognitive function during periods of restricted availability of food is a highly adaptive mechanism. If adult human brain function rapidly deteriorated as a consequence of underfeeding, the ability to obtain food would be significantly degraded, which from a survival or evolutionary perspective would not be desirable.

So, there is certainly no need to consume food upon waking in order to function properly from a cognitive perspective. And for some, like me, breakfast consumption may even impair concentration and focus for the remainder of the day.

  1. Lieberman et al. A double-blind, placebo-controlled test of 2 d of calorie deprivation: effects on cognition, activity, sleep, and interstitial glucose concentrations. Am J Clin Nutr. 2008 Sep;88(3):667-76

*More on this at the end of this post*

Feeding window

Q: “What are your thoughts about changing your window daily or weekly depending, Martin?

For example. I had my eating window from 13 to 22 yesterday, so I started my new window at 14 today. Now I’m thinking to eat my cals to 18:00 and then eat tomorrow @ 10:00 again. Seems logical?”

Answer: I would not recommend switching it up just for the sake of randomness. There are benefits in keeping the feeding window fairly constant, such as adaptations concerning the hunger hormone ghrelin (which tend to rise at times you’re normally accustomed to eating). Vary it for practicality’s sake, if anything.

Cortisol and fasting

Q: “Does fasting raise cortisol?”

Answer: No. Cortisol is regulated in a diurnal fashion and studies show that various meal frequencies and short term fasting has very little influence over it. Recent studies found no significant change in the rhythm of cortisol secretion, regardless of meal patterns, nor after 22 hrs of fasting.

Periods of environmental light are more important than meal times/frequency in regulating this hormone. Cortisol secretion is always highest in the early morning and lowest between 2000 and 2400 h.

Ramadan fasting alters diurnal rhytm, but leads to a decrease in mean cortisol.

Prolonged fasting and/or starvation is another deal.

Hunger and adaptation

Q: “13 hours in to my first day of IF and OMG I am hungry.”

Answer: The hunger hormone ghrelin adapts to your habitual meal pattern, meaning you tend to get hungry on the times you normally eat.

A few days of adaptation may be required. And this varies between individuals, as some people find fasting easy from the get go, while others require a few days for the transition to the new meal pattern to be complete (meaning the fasting will become more or less effortless).

Fasted workouts

Q:“I have done workouts on an empty stomach for over a half a year now and I think it’s better on empty than eating a regular meal a few hours before it. Biologically we humans are programmed very well to train this way.”

Answer: Yes, training on an empty stomach is not a big deal, had some fantastic fasted workouts myself, but like I’ve said countless times before pre-workout nutrition is almost as important as post-workout nutrition. This is verified by research.

Now, pre-workout nutrition doesn’t necessarily mean a full meal, but based on everything we know having some whey or BCAA shortly prior to, or during, the workout would be a much wiser choice than going through it completely fasted.

“Clean” eating

Q: “Ive been reading through the forums. I thought you have to get the clean foods like egg whites,chicken, fish, vegtables oats, sweet potatoe in order to get to 6 or 7% body fat. Some you you say you eat mcdonalds and cookies and still get the leanest you ever got. How is this possible when you see bodybuilders and most nutritionist on the websites saying you have to eat clean for you to get results? “

Answer: I’ve gotten ripped eating ice cream and cereal 3x/week. Clean foods are beneficial in terms of providing satiety and not providing as much temptation as ‘unclean’ foods or whatever you wanna call them.

I do agree that the majority of foods eaten on a diet should be clean*, but it’s not an all-or-nothing deal (even though a lot of bodybuilders make it out to be). Regularily including some unclean stuff, may help with diet adherance and protect against unplanned binges – and may ultimately help with diet maintenance in the long term.

* not interested in semantic analysis, everyone knows what I mean.

Breakfast again

(in reply to another question pertaining to the need of eating breakfast and studies on the topic)

There’s been heaps of studies “showing” that breakfast is good and healthy. How? Well, they’re correlational.


Breakfast eaters weigh less, as seen in a studiy looking at the eating habits and BMI of 10k+ US adults*


Breakfast must be good for you

* = eating breakfast implies fairly regulated eating habits.

That is, people who don’t eat breakfast are more likely to show dysregulated eating patters; average joe skipping breakfast sure as shit isn’t thinking “I’m doing IF now”. He’s the type to grab a donut on the way to work, eat junk food for lunch and finish the day off with a big dinner and snack in front of the TV.

Now, I’m not against children and teens eating breakfast, or anyone else for that matter, but given what I just demonstrated above, it might give you a hint on what the claim that breakfast = good for studying/tests is based on.

For example, breakfast skipping children probably usually come from different socioeconomic backgrounds/households vs breakfast eating children.

It may very well be that breakfast eaters —> perform better than breakfast skippers —> because they come from a familiy where breakfast eating is enforced —> this implies a supportive or “stable” family—> children from supportive/stable families perform better on school tests etc.

Just an example. I’m not familiar with the particular study your teacher refers to.

In adults however, it has been demonstrated that fasting does not impact negatively on various cognitive tests (as recently evidenced by a study that had participants fasting for 48 hrs).

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