I’m going to start IF soon to reduce (a) LDL and (b) inflammation. I really want to avoid losing weight, as I am already lean: BMI 20; height 180 cm (5’10") and weight 68 kg (150 lb). I’ve just got hold of Dr Fung’s ‘Complete Guide to Fasting’, and he advises not fasting when BMI is under 20.
I plan to start with 16/8, then progress to 20/4 (OMAD), but may not extend further than this due to having to take aspirin daily.
I’ll be grateful for any advice anyone can share.
I am normal weight (just a hair shy of 6’2 and 171 - 175 lbs) and my BMI is normal, and I still fast (OMAD) usually 5 days a week. My meals are large… very large large and nutrient dense. So yes, you can safely IF while being thin. You may not want to do long extended fasts, but IF… sure thing.
Higher LDL is associated with reduced all told mortality. Based on the current state of the evidence I’d probably be happier to see my LDL going up as long as I was healthy and LCHF.
Let’s reframe your question. You go to bed at what? 10,11PM and get up at what? 7,8AM. Whatever, the exact start and end times aren’t the issue. Assuming you’re asleep most of those 8 hours or so you’re not eating. That is essentially the definition of a daily 16/8 IF. So you’re probably already doing it. During the other 16 hours you eat normally, whatever that is. You don’t lose weight.
Go for it! 
Even the folks at IDM consider OMAD more of a maintenance weight WOE so you may be fine. If you find you’re dropping too much weight you could try increasing your intake of the more notorious ‘stall foods’ such as nuts & cheese.
I’m pretty sure your hunger hormones, ghrelin and leptin, will do their best to keep you at a healthy weight. I found that the closer I got to my goal weight, the more I became interested in eating and the greater my appetite became. These hormones, in a healthy metabolism, are our fail-safe to keep us from losing too much weight.
I’ve been in maintenance for the past two months and I’ve only been trying to eat intuitively and aside from the two weeks I was eating roasted sweet potatoes every other day and gained seven pounds, I’ve managed to stay between 172-176 pounds. Even when I eat the occasional one meal in a day, I just don’t seem to go below 172… which is fine by me because my goal weight is 175.
Hi Colin, I was on aspirin for over 20 years at doctors insistence. I was starting to get concerned recently because my blood was taking way too long to clot. I just stopped taking after an incident where I had a really minor skin ding on my forearm that took an hour of pressure to make it clot. And I did some reading on the risks and benefits of aspirin and decided that I did the right thing. My blood clotting is normal again. I finally saw my doctor and told him I had stopped taking it expecting him to protest my decision. He said “okay” 
. It turns out the benefits aren’t what they thought before (imagine that! 
) and they aren’t just telling everyone to take it as they get older. I don’t know why you need it, may be legit. And I am not sure that this was one of the articles I had read but I think it may have been.
Best wishes for your efforts. 
Megan Ramos, Dr. Fung’s co worker says OMAD is good for weight maintenance. She doesn’t think those trying to loss should follow that on a regular basis. In your place I would do the OMAD, use EVOO and avocado oil.
Good luck with it.
Thanks for this. I’m taking aspirin as I have a significant lesion in my LAD coronary artery.
I wonder whether I could take the aspirin with bone broth? That way, I could extend the fast beyond 24 hours.