Does intermittent fasting dull your mental edge? We crunched the data for the best advice

ABC(Australia) ^ | 11/04/2025 | David Moreau

[Kid Shelleen]

---SNIP--- Fasting is not just a trendy diet hack. It taps into a biological system honed over millennia to help humans cope with scarcity.

When we eat regularly, the brain runs mostly on glucose, stored in the body as glycogen. But after about 12 hours without food, those glycogen stores dwindle.

At that point, the body performs a clever metabolic switch: it begins breaking down fat into ketone bodies (for example, acetoacetate and beta-hydroxybutyrate), which provide an alternative fuel source.

This metabolic flexibility, once crucial for our ancestors' survival, is now being linked to a host of health benefits.

[Kid Shelleen]

Interesting read; their conclusion is that "People performed just as well on cognitive tests measuring attention, memory and executive function whether they had eaten recently or not."

[Segovia]

Then there is still hope! If the government stays shut down for a couple more months, and there’s no SNAP benies, all those Democrat voters will actually get healthier and smarter! Win/win!

[FreedomNotSafety]

Fasting improves mental clarity. It also produces an energy buzz after a 2-3 days.

[yldstrk]

Fasting improves mental clarity. It also produces an energy buzz after a 2-3 days.
********
Highly recommend.

[yldstrk]

So it’s better to eat yourself into oblivion.

[RoosterRedux]

I do intermittent fasts everyday in that I only eat one meal a day, usually before noon—sometimes before 9:00 or 10:00 AM. Sometimes I fast for a few days. My mental acuity is always significantly sharper fasting.

A meal often makes me slightly sleepy.

I eat low carb BTW.

[deport]

is now being linked to a host of health benefits.

**********

Losing weight to some degree is beneficial or so
it is claimed. Eat enough to sustain a proper
weight but not more that gains weight to be
carried around daily. Keep dem calories flowing
rawhide.

[alloysteel]

The first 24 hours of a fast is the hardest. After that, the body has made the metabolic shift, and 96 hours becomes about optimum for a water-only fast, then reintroduction of reduced calorie meals for at least a week, which resets the body’s basic metabolic rate.

[RoosterRedux]

Fasts longer than two days noticeably sharpen your sense of smell. I can literally smell a hamburger grilling from miles away.

The first time I realized it was during a five-day fast. I was driving to a small city on business with the windows down, enjoying the weather. I figured I was still five miles out when the smell of grilling meat suddenly hit me—strong and unmistakable.

About a minute or so later, I came around a bend and there was a whole strip of fast-food places. It was striking how much more sensitive my senses had become.

[woodbutcher1963]

My wife and I started intermittent fasting last December.
I am 62. She is 61.
I am 5’9” and WAS 213 pounds last December.
We fast typically twice per week. From Sunday night after dinner until Tuesday morning. Then again from Wednesday night after dinner until Friday morning.

After 11 months I now weigh 178-185. This morning it was 181. The only thing other than water I will drink today is 10 oz of black coffee about a half hour ago.

In addition to loosing 30+/- pounds my chloresterol has dropped(as of last January when I had my physical) from 265 to 205. This was only when I had lost about 15 pounds. I suspect it is lower now. I have had genetically high HDL/LDL all of my adult life. I tried and ceased use of five different statins because of muscle weakness.

As you/others have mentioned the hardest part is getting through the first 24 hours. I have never done more than the 36 ish hours. Lastly, I also stopped drinking alcohol last January 1st and did not drink again until April. So, that helped in the initial weight loss.

This is the only thing that has worked for me to have a significant weight loss.

[montag813]

Matcha, Rhodiola and L-Tyrosine is what keeps me energized throughout my day despite the fact that I do 18:6 fasting every day (I eat last meal at 6pm and next at noon next day).

I went from 215 lbs to 150 (with semi-regular exercise). When I switched from coffee to Matcha, I finally lost the belly fat that would not go away. Matcha has caffeine+theanine and EGCG which studies have shown can double your calorie burn. I use a frother with the matcha and water, with almond milk and Allulose (RX Sugar), which is the one of the only calorie-free sweeteners that has not been linked to heart issues.

These are what I use:

Now Foods L-Tyrosine 500mg, 300 Capsules - Non GMO - Supports Mental Alertness

Pure Encapsulations Rhodiola Rosea - Endurance & Fatigue Relief

Sencha Eveyrday Natural USDA Organic Matcha Green Tea Powder Rich Antioxidant Revitalizing

[Dacula]

I’m right with you. I have been fasting for about a year and have lost 75#s. The only problem I have is that I have to buy new pants. I lost 6”s around my waist.

——My wife and I started intermittent fasting last December.
I am 62. She is 61.
I am 5’9” and WAS 213 pounds last December.
We fast typically twice per week. From Sunday night after dinner until Tuesday morning. Then again from Wednesday night after dinner until Friday morning.

After 11 months I now weigh 178-185. This morning it was 181. The only thing other than water I will drink today is 10 oz of black coffee about a half hour ago.

In addition to loosing 30+/- pounds my chloresterol has dropped(as of last January when I had my physical) from 265 to 205. This was only when I had lost about 15 pounds. I suspect it is lower now. I have had genetically high HDL/LDL all of my adult life. I tried and ceased use of five different statins because of muscle weakness.

As you/others have mentioned the hardest part is getting through the first 24 hours. I have never done more than the 36 ish hours. Lastly, I also stopped drinking alcohol last January 1st and did not drink again until April. So, that helped in the initial weight loss.

This is the only thing that has worked for me to have a significant weight loss.

[woodbutcher1963]

GOOD for YOU!
Congrats

I have dropped from 38 to 36 being a little loose.
I still had a lot of pants hanging in the closet I had not worn in years.

I do find myself wearing warmer clothes more often.
I am wearing a button down shirt and a long sleeve cotton sweater to the office today. Meaning losing that much body mass, I get cold easier.

[Kid Shelleen]

Thanks for that info; it seems like the 18:6 fasting is a great way to start.

[Dacula]

Thank you. I am constantly freezing. I attribute it to the loss of insulation. :) I need to go through my closet and get rid of clothes that I haven’t worn in years. I have separation anxiety about getting rid of stuff. I feel like I might need it someday. grrr.

---

GOOD for YOU!
Congrats

I have dropped from 38 to 36 being a little loose.
I still had a lot of pants hanging in the closet I had not worn in years.

I do find myself wearing warmer clothes more often.
I am wearing a button down shirt and a long sleeve cotton sweater to the office today. Meaning losing that much body mass, I get cold easier.

[woodbutcher1963]

I took a couple bags just recently to a buddy who runs the local St Vicent DePaul at our church.
That way the clothing/coats actually stays in the city of Manchester. Instead of being shipped to Africa/South America or elsewhere.

Like all those T shirts for the team that does NOT win the SuperBowl. Right now, there is probably a container of Toronto Blue Jays World Series champions hats and shirts headed to some third world country.

FYI, my wife bought me a ORORO (brand name) battery heated vest last year for Christmas. It is great for those days when you don’t need a jacket or first thing before the car warms up. I also use it for deer hunting. When you are sitting still in a tree stand for 2-3 hours in NH waiting for some horny buck to walk in front of you. It works great.