Intermittent fasting – not so great?
Intermittent fasting on various schedules is touted as being an effective weight loss tool, but it didn’t do a thing for me. Here’s some recent research:
The findings suggest it may be calorie reduction rather than time-restricted eating itself that boosts key indicators of health inside the body, although it’s important to bear in mind this was a relatively small-scale, short-term study.
In addition to the study’s modest reductions in body weight, researchers observed changes in participants’ body clocks. The timing of their circadian rhythms, including those that nudge the body towards sleep, was shifted based on the TRE schedule.
And yet the intermittent fasting approach is very popular for weight loss. Here’s another study, this time from 2020, that isn’t exactly a recommendation:
The currently popular diet of intermittent fasting that restricts eating to eight hours per day, separated by 16 hours of fasting, is not effective on its own as a means of either losing weight or for improving key metabolic health markers, according to a new study led by researchers at UC San Francisco.
While time-restricted feeding has been shown to prevent weight gain in mice on a high-fat diet and reduces weight and metabolic outcomes in already obese mice, most of the reported benefits of such fasting in humans has had limited scientific testing.
Have you ever tried it?
I started intermittent feasting in November, but now I can’t see my scale, so results are unclear.
Yes, and it works for me.
The purpose of “intermittent” fasting (I prefer the term “periodic fasting”) is to flush the glucose out of your system and trigger autophagy. It depends more on the length of the fast than any intermittedness.
Since my big diet a few years ago, I often skip breakfast if I don’t feel hungry. I’ve kept most of the weight off.
What seems to have worked is that I still avoid fast carbs, I naturally eat smaller portions and I get uncomfortable if eat too much.
I doubt intermittent fasting has much benefit without changing what you eat and how much you eat.
I read the original article and I didn’t think it said what the headline characterizes it as saying.
Key point here:
No, you would not expect them to lose weight if they are just shifting their calories around.
In addition, this isn’t “fasting” as most people think of the word:
So they either skipped breakfast and ate more at lunch and dinner to make up for it, or skipped dinner and ate more at breakfast and lunch to keep the calories the same, or they had three meals like they usually do but ate breakfast late or dinner early.
The study only looked at timeshifting when you eat while keeping the total calories “the same”, but it’s being presented as though it discredits intermittent fasting in general.
“The same” raises another issue: who controlled the diets of the participants? If they did it themselves and self-reported, that’s always been unreliable.
The second sentence of the article is more accurate than the headline:
Yeah, you barely change anything, and you get barely any result. I don’t think that’s particularly new or surprising information.
A few years ago I did it pretty hard core and dropped about 20 pounds of excess weight, and about five inches off my waist.
Here’s the thing though… it’s not easy to sustain for the long-term or on a permanent basis. I combined it with a Keto intermittent fasting regimen and that was tough to keep up after about a year.
Long ago, our Doc suggested that we try the fasting. So, we dropped Breakfast in the mornings, instead would eat anywhere from 10:30 to noon. Dinner would be 5:30 to 6. It did help, some. But I still follow this pretty much. Say, Coffee and a piece of fruit in the mornings, then brunch. Dinner I eat later, anywhere from 6 to 7. Big change for me was no snacking on chips. Yes, I have been eating snacks lately, mostly candy. But when the candy is gone, it’s gone.
In late 2024, were were staying at a Residence Hotel in Denver, close to the Hospital where my Wife was getting treatment. Paid for by the Drug Co., plus money for Grubhub. In 5 weeks I gained 10 lbs. Took last yr to lose 20lbs, have gained 4 back. Working hard (mostly) to lose those 4 and maybe some more. Going on a Cruise in Feb, so weight will come back. But, I will watch what I eat, walk as much as I can. Right now, I walk when I can, and am going back to the Gym. Not hard, nor long, workout. But still going.
‘going back to the gym. Not hard, nor long, workout. But still going.’
^^ This ^^
Intermittent works for my husband but he also eats low fat/high protein.
I can’t do strict 16/8 but if I want to lose a few pounds a 14/10 schedule is doable. And sometimes that stretches out to the full 16/8.
It does seem to rev up my metabolism a bit.
Still have to cut out sweets and peanut butter, though.
Waaa!
I did “IF” for about 9 months and lost about 50 lbs doing it. But I also stopped nearly all sugars, stopped all snacking, only took 1 serving for meals (no seconds ever), so my caloric intake was down significantly as well.
It took about 2-3 weeks before I started seeing weight loss so at 1st it seemed to not be working, but then when it finally “kicked in” I lost about 8 lbs that 1st week, then a more reasonalble 1.5-2 lbs a week.
And then when I lost the 50 lbs I stopped being so stingy on my calories and even though I was keeping the schedule, I started to slowly gain weight again before finally abandoning the schedule also. I never started binge eating, so it took me about 8 years to gain that 50 lbs back, but… I gained it back.
So yeah, put me in the “it’s the calories, not the schedule” camp as well.
I have never had a weight problem, but have had some periods of gastrointestinal distress. Reading about research into the gut biome over the last decade led me to focus my eating to include more leafy greens, chickpeas and other sources of fiber, as well as plain yogurt and occasional fermented vegetables, kimchi, and sauerkraut. Stomach and GI tract are doing much better.
However, I’m genetically disposed to have higher blood sugar levels. Nothing serious, but primary care doctor says it’s pre-diabetic. So for six months I tried intermittent fasting, with two smaller but nutrient dense meals about five hours apart. No snacking, except for occasionally cheating with a few walnuts or almonds now and then.
Was tested once during that period, and again at the end of the six months. My blood sugar levels dropped from just over the desired maximum level to about between the lowest and highest normal values for the tests. So there was some improvement, but nothing spectacular, and I can’t say that I felt better or worse. So I am back to eating a decent breakfast, light lunch, and more substantial supper. My GI tract seems to prefer that, and my weight is actually going up as my more intense gym work is adding muscle. Belly will get tightened up once the holiday cookies are all gone, ha!
Calories, it’s mostly about calories. I have done intermittent fasting, but I also reduced the calories I ate. It worked, but as others have pointed out, it’s difficult to follow if you aren’t a hermit.
Sugar, refined flour, and all products containing those items make it harder to lose weight. They are turned into energy very fast and if you don’t need the energy, they will be turned into fat.
Complex carbs, proteins and fats are digested more slowly and tend to match our energy output (basal metabolism) better. However, when you take in too many calories of any food, it will be stored as fat.
In order to lose weight, you need to know your basal metabolic rate – how many calories your body burns per day. Eat less than that, and add some exercise – voila, the weight will come off.
Yes, in our world of food being easily available at all times, it’s not easy. It requires iron discipline on a long-term basis. 🙁
Eating complex carbs ad proteins will help decrease your appetite, and there are only 4 calories per gram of intake. Fat is okay, but it has 9 calories per gram. It adds up much quicker. Go easy on the fats.
The KETO diet is a bit like the GLP injections. Eating only protein and fat tricks the body into thinking you are full by inducing ketosis in your system. It works, but long-term use may have damaging effects on the kidneys. There’s no free lunch when it comes to weight loss. 🙁
My knowledge of weight loss comes from a life of trying to keep my weight in a normal range, and four years of participating in body building competitions. So, it’s anecdotal and may not apply to every case.
I have the impression that every few years, the literature in clinical nutrition discredits what was published during the previous bloc of years.
It worked wonders for me, but not for weight loss. My cholesterol numbers, particularly triglycerides, were out of control. Dietary changes didn’t budge them. Medication did. My numbers were still in the red, but much better. 5/2 fasting consistently keeps them all in the black (normal ranges). When I do a blood test I already know what the results are going to be. If I’ve gotten lazy with the fasting they’ll be red, if I’ve been good with the fasting, all black.
I know someone whose primary care physician once remarked that he (the physician) fasts one day a week (Fridays, I think, according to this friend). For what it’s worth.
Husband and I naturally do something like IF. We just aren’t hungry in the early part of the day. I eat in the early to mid afternoon and then again for dinner, and husband doesn’t all day at work and then eats a big dinner.
Eating more frequently tends to just make us hungrier.
I generally fast for 12 hours or so every day: usually between 7PM and 7AM.
Mike Plaiss brings up a good point re: his cholesterol. Namely, that metabolisms differ and some diets work better in different ways for different people.
For example, people who are diabetic or pre-diabetic have their own special dietary concerns.
My latest fave French YouTuber is Lucille in Paris. Here’s one of her videos to the topic point:
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French people never diet but have a balanced way of eating and a good relationship with food. Let’s see together why French people don’t get fat while still eating pretty much whatever they want!
–Lucille, “Why is it so Easy to be Thin in France?”
https://www.youtube.com/watch?v=sHKXlAnVgo8
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She attributes it to:
* Food quality
* Small portions
* Active lifestyle
* Home cooking
* Eating is a social event
* Meal times are structured
* Children are taught to eat adult food and cook early
* Peer pressure
* Staying balanced
My impression is that French society is more disciplined and structured than America.
All diets work if you stick with it.
Find the least uncomfortable and don’t give up.
And once you lose the weight, stay with the diet.
Don’t be like the sober alcoholic who believes one drink once in a while will be fine.
I started intermittent fasting about 10 years ago. It did nothing for weight loss but almost immediately I felt better, so I’ve stuck with it. After the first few days I didn’t miss breakfast* at all and found I was no longer hungry. I’m also less hungry at lunch, and don’t eat much until dinner.
I didn’t lose weight with IF, but it may have helped me not gain weight as I age. Most my peers seem to have put on a few more pounds in the ensuing decade, where I haven’t. I still have about 15 I’d love to lose to get back to where I was in my 20s and I’m going to try the slow carb diet huxley has written about. It sounds like a good fit for me. I’ll also stick with the IF, just because I have more energy doing it, although I may experiment with a hard boiled egg or two in the morning while doing slow carb to see if that matters.
I won’t be surprised to learn there are no health benefits from IF. I’d concluded that is likely true myself over the past decade. It’s just a better fit for me, my metabolism and lifestyle than 3 meals a day.
*Although breakfast foods are still my favorite. I often have eggs for lunch or dinner.
Intermittant spelling…
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WRT IF, seems to me that it can be very useful in establishing (and sustaining) better eating habits: i.e., if it helps those who should be eating less (IOW those who should be reducing their caloric intake) to in fact do so.
Huge meals aside, if IF is followed, it should help people reduce—perhaps even eliminate—snacking (or indiscriminate snacking) and/or change snacking habits to eating healthier snacks and/or replace snacking with healthy (or less problematic) beverages, i.e., teas, water, soda water—either pure or used to dilute pure fruit drinks, lemon/lime or herbs…).
I think the issue is to avoid having one’s digestive system overloaded and/or working too often.
Better for the entire system.
The question is how to do that; how to start doing it; how to maintain doing it.
Snacking is so, so easy…
Perhaps chewing a natural chewing gum, assuming such a product is available, might be a strategy, at least at first.
And for some intermittent sanity (IS)—or even more than intermittent—here’s Ayaan Hirsi Ali…
“Britain Is Facing Islamic Conquest: An Interview With Ayaan Hirsi Ali”—
https://blazingcatfur.ca/2026/01/11/britain-is-facing-islamic-conquest-an-interview-with-ayaan-hirsi-ali/
And not just Britain…
(Just think of her as a Political Nutritionist …)
I PROMISE anybody interested in weight loss–restrict your carbohydrates to 20 grams a day, and you will lose the weight you want to.
I have witnessed hundreds of people doing so in the past twenty five years.
Mainly physicians and nurses, but plenty of patients too.
It is virtually metabolically/endrocrinologically IMPOSSIBLE to not lose weight with the low insulin levels that result.
If you aren’t, it is because you are not stopping at 20 grams of carbs.
RADICAL HONESTY here people–what is going in to your mouth????
(I guess you could have some really weird steroid producing situation that would cause you to retain fluid, or an insulin producing tumor.)
No, you are not going to damage your liver, your kidneys or your arteries in doing so.
Your lipid levels do NOT matter, unless you have a heriditary hyperlipidemia–it’s your TG level. Which will be less than 80 if you limit your carbs.
(Well, I am all about not ingesting seed oils too. So stick with butter, bacon grease, tallow, lard, olive, walnut, avocado oils.)
As I tell my children:
CARBS KILL!!
(And yes, they taste delicious! I am a chip person. ADORE them.)
YOU are responsible for about 90% of your health.
Real food, and exercise. it will save your brain, your heart, your entire body.
Hit Jason Fung’s Diet Doctor site, Mark’s Daily Apple–it’s accessible and out there-FREE–and has been , for decades now.
Gary Taubes will tell you all you need to know.
If your doctor isn’t telling you this–especially if they refute it–find a new one. Because they are NOT keeping up.
People make the mistake of confusing living forever with living well. Unless you’ve got chariot driving skills you’re going to die, live well ( maybe longer) and you’ll be happier.
lee:
Been there, done that, did not lose weight. In my 20s, I went on what was then called the Stillman Diet. Very low carb. I only ate meat or cheese, plus only lettuce or green beans for vegetables, no fruit or grains at all and of course no sugar. I did that for one month and lost something like 1/2 pound.
I’ve discussed Taubes et al many times on this blog. It doesn’t work for weight loss for everyone. Period. Plus, that sort of eating makes me feel ill.
I’m not and never have been mega-overweight, though. It’s usually been between 10 and 20 pounds I’d like to lose.
It’s spelled “intermittent.”
And yes, it works, IF you eat two meals a day instead of three, without increasing total calories. I do the 16:8 plan several days a week. It’s hard to get enough protein in while eating only two meals, and it’s hard for women in the later decades of life to lose weight .
@neo: [Taubes] doesn’t work for weight loss for everyone. Period.
Finding a good diet isn’t an engineering problem matching inputs with desired outputs that works all the time for everyone.
Human response to diet is quite complicated. We evolved in many different environments and evolved to optimize response to the diets of those environments. Then we spread out all over the globe and interbred.
Who knows what genetic hand you’ve got to play when it comes to diet? As well as your current medical history.
I tried the Slow Carb diet and it worked for me. I could stick with it, get results, and feel good, so I did not have to rely on pure will power.
So I think people have to experiment and find what works for them. Sure, read about different diets and try them, but don’t necessarily expect the same results.
The phrase “intermittent fasting” implies that there’s some other kind of fasting, while in reality, ALL fasting is intermittent fasting. Fasting that isn’t intermittent is known as starvation.
Also, skipping a meal here and there doesn’t qualify as fasting. You have to go without food longer than a few hours to achieve the state of autophagy, which is when the benefits begin.
The reason diets fail is that they are not sustainable over the long run, so people eventually go off of them and promptly gain back all the weight they lost. Fasting is easier and more effective, and I have found it perfectly sustainable. I’ve been fasting for 36 hours three times a week for more than five years now, with excellent results.
Title spelling fixed.
My great wisdom on diet, exercise etc.?
You can’t outrun the fork.
@bluebird of bitterness: Also, skipping a meal here and there doesn’t qualify as fasting.
Not so:
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fasting, abstinence from food or drink or both for health, ritualistic, religious, or ethical purposes. The abstention may be complete or partial, lengthy, of short duration, or intermittent.
https://www.britannica.com/topic/fasting
I was a Catholic kid. It seemed we fasted all the time under complicated rules.
I understand the rules have been relaxed since then, but autophagy had nothing to do with it.
I’ve struggled with weight issues my entire life. My pediatrician even prescribed diet pills when I was 10 years old in the ‘60s. My weight eventually stabilized in my 20s but I always have to be vigilant because I tend to put on weight more easily than most people I know. The only method that has worked for me is this – eat only when you feel hungry and stop eating when you feel satisfied.
I hesitate to call it a diet because it doesn’t involve what you eat or when you eat it. But it works for me if I need to lose weight (like after the holidays) or want to maintain it.
I lost 65lbs over an 18-month period and have kept it off. It knocked off diabetes and cholestrol issues.
I did zig-zag fasting which never lets the body adapt. About 1400 calories 3x/week (keto breakfast +snack lunch+ carb dinner + gym) and about 1,000 calories the other 3 days (low calorie carb breakfast + snack lunch + keto dinner). One day cheat meal but with 110 calorie protein shake for breakfast and lunch along with 10,000+ steps on that day brings the calorie count in line. Ideal for somebody like me with 1,350 BMR.