Intermittent fasting for women?

August 7, 2018 6:23 PM

There are a ton of “health journalists” (content creators) on the web arguing about whether women should use intermittent fasting (IF) to lose weight/improve their health. If you’re a woman who’s done IF what’s your experience? Or if you’re an actual serious health scientist, what do you make of the literature?

I’ve lost about 20 lbs over the last year with traditional calorie cutting. I currently don’t exercise outside of a lot of walking and some light bodyweights almost every day (squats, push ups, etc.). I’ve been plateauing for awhile and would like to sustainably lose about 30 more pounds.

After hearing about IF, I realized I’ve been kind of inadvertently doing it during my “best” diet weeks— fasting for about 14 hours total (overnight + morning) for most of the days per week. Sometimes I would find it hard to sleep and eat a little, but otherwise I was essentially eating three meals and one snack in a ten hour period and nothing else. I was probably never consistent about it for more than two weeks at a stretch. I felt basically fine during these periods, sometimes even better than normal.

However, health websites and blogs are all over the place about whether women actually get the non-weight loss benefits that men do— less sensitivity to sugar being a big one, I gather. If you’re a woman who has intentionally done IF, for weight loss or other reasons, how did it go for you? And is there actually solid and compelling evidence that IF screws up women’s bodies (hornonally I guess), or is it more an absence of research on women?

As an example of the kind of stuff I’m reading, there is a Prevention article “debunking” the popular Crescendo Method and claiming IF for women is fine here. Whereas here’s an article of some scientific substance (can’t judge well myself) claiming women have been bamboozled into fasting and should not really mess with it.

posted by stoneandstar to Health & Fitness (11 answers total)

Valter Longo is the scientist working on this, though he would say that if you eat every day, you're not fasting - he would call what you're describing "time-restricted eating." I would recommend his book, The Longevity Diet. He has also appeared on a bunch of podcasts - if you want to go in depth, I'd listen to him on Found My Fitness. He is more focused on longevity than weight loss per se though.

I've been doing time-restricted feeding since August. I'd say I've lost about five pounds from that alone. I go thirteen hours a day without eating - from 7 pm until 8 am. Longo says that if you go longer you're risking health problems, specifically gall bladder problems. The major benefit I've noticed is that this has pretty much cured my chronic insomnia. In fact, I ended up eating a muffin late at night a few weeks ago and couldn't sleep at all. I have not lost a huge amount of weight from just the time-restricted feeding, but I've lost 35 pounds in the past year by just tweaking my diet - I change something, lose five pounds, keep it off for a while, then change something else.)

I have not heard Longo say anything specific about why women should or should not fast. He has developed a commercial product called Prolon, which is a fasting-mimicking diet (very low calories, but you get the health benefits of fasting). You stay on it for five-day periods once a month at the most. It's only available through doctors - I can't do it because I currently have cancer (he's working on something for cancer patients, but it's currently in clinical trials). It's not cheap - but all profits go into his research. I've heard him say that he decided this really has to be supervised after some woman trying something similar on her own died. (I think she might have read his book in Italy - it was first published in Italian, his native language.) Prolon is supposed to help with weight loss.

(I know people tend to get suspicious of doctors selling products, but I think there are valid reasons to sell this as a product. This is carefully researched, and his primary interest is longevity - it's not NutriSystem.)
posted by FencingGal at 6:58 PM on August 7, 2018 [2 favorites]

I have been doing intermittent fasting for non-weight-related reasons for about two months. I haven't lost any weight that I've noticed, but I have seen a number of other benefits. Honestly, I am skeptical of many of the claims, both for and against. Humans have eaten in many different ways for millenia, so I very much doubt that one particular way is The Way we are supposed to eat. In addition, many women take hormones for contraception or menopausal reasons without a second thought (myself included) but I'm supposed to worry about the time of day I eat affecting my hormone levels?

I figured it would be worth trying because if it didn't seem like it was working I could just...eat something. But I saw immediate improvements in my alertness level in the morning, my ability to avoid sugar throughout the day, the impact of the afternoon slump, the amount of water I drink, and my grocery budget. It does require consistency though - I didn't stick with it on vacation and I went back to feeling crummy. Back on the horse and it's getting better again.
posted by peanut_mcgillicuty at 7:33 PM on August 7, 2018 [7 favorites]

I've been doing 16:8 (16 hours of fasting and 8 hours of eating) for about a month now. Hard to say exactly since I don't weigh myself every day, but I think I've lost a few pounds. I've definitely noticed some pants fitting better and that kind of thing. I feel good in the mornings and I haven't really noticed any difference in hormones (ie mood swings, acne, etc - though I'm on hormonal birth control).

The r/intermittentfasting group is pretty active, so you may want to check that out for additional anecdotes. Best of luck!
posted by too bad you're not me at 8:20 PM on August 7, 2018

I've tried 5/2 intermittent fasting a couple times, the longest was for about 3 months. I did not have much success from a weight loss perspective and quit because of insomnia and mood issues. My (postmenopausal) mother and father have had GREAT success with it though. They have lost a bunch of weight and have been able to reduce or quit a couple of medications for some chronic health issues. So I think it varies based on the person, but anecdotally, I thought it might have had a greater impact on my hormones compared to other types of dieting I have done.
posted by mjcon at 8:53 PM on August 7, 2018

Just an experience here.

I did OMAD (one meal a day) for 3-4 years. I only ate dinner and after dinner fruit/dessert, so I guess only ate between 8pm-11pm.

I didn’t do it every single day, but did it at least 5/7 days (work days). I felt 100% fine, good even. Didn’t ever feel faint, didn’t feel particularly hungry, never got headaches, and found it easy. I kept well-hydrated. I work a busy job with long hours and often no time for a real lunch break which helped. I also ran 10-20 miles a week doing this without any ill effects - in fact I think it made my properly-fuelled races faster.

I only stopped due to pregnancy.

I was always made to feel weird about all this by basically everyone I encountered but I loved it. It allowed me to lose weight whilst still having a big meal each day. I still had to calorie count to lose weight but it made sticking to 1200/day much easier.
posted by peanut butter milkshake at 11:07 PM on August 7, 2018 [8 favorites]

I lasted less than a couple of days. I knew it was a bad idea for me because despite not being diabetic or prediabetic, I’ve *always* had terrible reactions to missing or even delaying meals - headaches, nausea, crabbiness - and often later binged to compensate or made poor choices... IF adherents say this eventually passes, I just did not find the pain worth it at *all*, considering regular calorie counting plus exercise works just fine. (Imo the more conservative the deficit, the better - it does take patience but causes less suffering and is infinitely more tolerable and sustainable than an aggressive cut.)

I think this is researched to an ok degree (for a health content article, sources are at the bottom). TLDR (according to them), yes fasting can throw metabolism and hormones off (by screwing with the timing of things) and increase stress, any of which can affect reproductive function and/or hasten menopause. (Bear in mind that women vary in sensitivity to hormones.)

(How tall are you? People on the short side inevitably have a harder time when they get closer to their goal weight, because you have to leave your body something to work with. Many people just add some cardio to increase the deficit, or they’ll adjust their expectations re the timeline.)
posted by cotton dress sock at 12:24 AM on August 8, 2018

I'd been eating like a lawless murderclown for a couple of years and gained forty or fifty pounds, which I'm now shaving off slowly. I used to skip breakfast but the dentist said I had to seriously brush my teeth twice a day--with the whole floss routine and all--which seemed stupid if I hadn't eaten anything since the last flossing session, so now I skip dinner. I like dinnerskipping a lot. It means even something relatively meager eaten after dark, like a tiny cup of yogurt with a spoonful of honey on it, feels like a feast. A real dinner? Decadent bacchanal. I like to have a lil cup of tea at night. Occasionally I'll put some cream in it. Sometimes I'll have a mug of broth.

It's been about two and a half months and I've lost 20 pounds, but I also quit drinking, sugar, fruit, and bread/potatoes/rice/noodles. I feel normal; it took a week to kill my sweet tooth so I'm not thinking about eating all the time. Now I'll putter placidly through the day and then realize, wait, I feel a little faint, maybe I should eat? Oh, yes, it's been six hours since breakfast.
posted by Don Pepino at 3:59 AM on August 8, 2018 [4 favorites]

Another benefit of not eating after 7 pm is that I feel like I have tons of time in the evening to do other things. It's amazing how much time you can spend thinking about food, preparing food, eating food, and cleaning up after eating food. When all that's off the table (so to speak), the whole evening opens up.
posted by FencingGal at 7:13 AM on August 8, 2018 [3 favorites]

Best answer: I have been intermittent fasting (16:8) for about a year now. During the eating window I do not calorie count. I eat pretty much whatever I want.

I did not start IF to lose weight, and I have not lost weight. I have not, however, gained weight. This, despite going through some tough times this past year -- occurrences which would usually cause me to gain 5+ pounds just from stress and disrupted routines. My husband and I did this together and 90% of our meals are the same. His cholesterol and blood pressure is significantly improved (was able to stop some medications).

I have higher energy and never get “hangry” anymore. I can go several hours past the start of the open eating window and not even notice (when busy). In the beginning, I definitely noticed that I was sleeping better. I have gallbladder issues. Since starting IF, I experience much less pain and general discomfort with eating.

I do not think it has changed my menstrual cycle at all (I am not on hormonal birth control). Sometimes, usually the first day of my period, I may feel draggy and headachy in the early morning, and if I do, I go ahead and eat, and that helps. I also don’t worry about special occasions or whatever - if I’m invited to a meal that doesn’t conform to my timeline, it’s no big deal. Just eat and enjoy.

If you have any history with disordered eating, this may not be the best choice for you (there was recent AskMe on this subject if that applies to you). Ultimately, weight loss comes from calorie control and exercise. Intermittent fasting alone is not a substitute for that. It is not a golden ticket to weight loss. N calories consumed over 8 hours is the same amount of calories consumed over any other period of time.

I love IF especially because I love food, I love cooking, I love eating. IF lets me enjoy food more than I did before. I can eat bigger, richer meals with no ill effects.

This is my personal experience. Your mileage may vary. Bodies are unique.
posted by slipthought at 7:26 AM on August 8, 2018 [1 favorite]

Response by poster: I should clarify that I’m doing (mild) IF along with calorie restriction— I didn’t actually research whether that matters.
posted by stoneandstar at 8:49 AM on August 8, 2018

Time-restricted eating has worked well for me over the last two years, and I haven't seen any issues with my hormones, blood sugar, or anything else in my recent blood work.

I'm petite (five-foot nothing) and live on my own, and I found that the number one reason I gained weight in the past was by "rounding up" on servings based on how much was in a package, on a restaurant plate, or even in just the "natural" portion size of how big a chicken breast or slice of bread is. Eating three meals a day was adding extra calories that I didn't need and wasn't hungry for just because I wanted to clean my plate or not have to alter my recipes down to half an egg or three-quarters of a roll in a world that's designed for the caloric needs of more sizable individuals and families.

Cutting out breakfast just simplified things for me. I eat a full lunch and full dinner, and I have a snack if I get hungry. It just adds up to a better amount of food for my frame with less planning on my part.

The one improvement was actually in my blood sugar, in the sense that I used to really feel it if I ate breakfast every day at the same time during the week and then overslept by an hour on the weekend. I never sleep long enough to miss lunch, so I don't get the wooziness or headache I used to get from a late meal.
posted by northernish at 1:46 PM on August 8, 2018 [1 favorite]