5:2 diet on Soylent

So, is anyone trying the 5:2 diet while on Soylent?

5:2 is the diet where you eat whatever you want (within reason) five days a week, then calorie-restrict the other two days. For women, fast days are 500 calories; for men, 600.

I’ve been on 5:2 since Dec. 2013 and have lost 25 lb. – down to 158 from 183. I’m a 5’4" female so theoretically I ought to weigh 145, max. My doctor’s watching me closely and there haven’t been any negative health effects; measures like glucose and cholesterol have shown some improvement, even, from slightly bad to back in the normal range. I tend to use Soylent as breakfast and lunch on non-fasting work days, but am considering also using it for my 500 calories on fasting days. Has anyone tried it? And, if so, any satiety issues? (Other than the normal satiety of wanting more than 500 *!$!%! calories a day, of course.)

Thanks in advance for your input!

Personally I think I’d have to do the opposite of your proposal to make that diet work, since Soylent is sort of my go-to to replace the junk in my normal diet and without it I’d end up going overboard during the week, but that’s neither here nor there.

To answer your question about satiety, it seems to be pretty varied. In my own experience I’m usually pretty satisfied (even ‘full’) after even a small amount of Soylent, though lately I’ve been feeling a little peckish much sooner for one reason or another. Others have had the exact opposite, where they find it unfilling initially but adjust to it. Unfortunately there’s no one-size-fits-all answer since it depends on so many other factors, but if you’re used to calorie restriction it shouldn’t be too much worse than usual.

If you’re eating only 500 calories on those days, though, you might be a lot more satisfied eating piles of raw veggies rather than, say, a 16oz cup of Soylent.


Good point, thanks. Yeah, I usually spend my 500 calories on a lot of veggies held together by some scrambled eggs and hot sauce, so it could be hard to switch. :smile:

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I wouldn’t recommend it… on the two restricted days, you should try to make most of your calories come from protein, to avoid muscle wasting. You want to minimize muscle and organ loss, so that the majority of your weight loss is in the form of fat.

For those two days, I think you should be trying to do a PSMF: protein-sparing modified fast. Which means to eat greens, non-starchy veggies, and lean proteins, with nearly all of your calories coming as protein.

This matters more and more as you get leaner - the more fat you have, the more you’ll tend to lose fat, but as your fat ratio declines, you’ll start losing more and more lean tissue when you do this.


I’ve been debating on doing Soylent for Lunch and Dinner 5 days a week for 4 weeks per month and eat small/healthy meals on the weekends. I think I am going to alternate Soylent for lunch or dinner throughout the month (once a day) and eat a small meal for the other meal of the day.