Fasting Mimicking Diet on Soylent


Has anyone else tried a Fasting Mimicking Diet on Soylent? I already generally follow Intermittent Fasting (time-restricted eating) and try to eat my meals (50% Soylent) in 10 or fewer hours of the day, but I read about the potential benefits of the FMD and figured Soylent might fit the bill just about perfectly.

The general idea is to get the same benefits of something like a 3-day water fast, but in a much easier and safer way by still eating food every day (800-1000 calories a day for 4-6 days). The food you eat needs to be very balanced and contain plenty of vitamins/minerals, so that’s why I figured Soylent would be great.

I decided to give it a try a couple weeks ago and it went great. I drank 2 bottles of 2.0 a day and then snacked on some mixed nuts to get some extra sodium and fat/protein. I also added some electrolyte powder to a glass of water every day and took a multi-vitamin every other day just to be extra safe that I was getting everything I needed.

Overall I’d say it was quite easy to do. I was definitely hungry, but never to an extreme, and I always knew a small amount of food was just around the corner. My energy level was fine throughout, and had a big boost once I started eating normally again afterwards. I felt amazing those first few days afterwards. You’re supposed to avoid exercise while on the fast, but then once you start eating again, you’ll get a boost to muscle growth, and it definitely seemed like I managed to convert some fat into muscle. I visibly lost some minor flab around my stomach/waist, had to notch my belt a little tighter, but yet shortly after the fast I had only lost 3lbs (I’m not overweight at all, so it’s good I didn’t lose much if any weight).

I’ll definitely be doing it again. The FMD should not be done more than once a month to give your body time to recover, and many sources suggest doing it every other month or so, but I think I’ll likely stick to just a few times a year.


I’ve maintained a Soylent exclusive diet as a 30 day challenge a few times in the past. I definitely had way more than 1000 calories though, in total it has ranged from 1600-2500 each day.

I’ve never heard of a “Fasting Mimicking Diet” though, I wonder what the idea behind it is. I’ll have to look into it! :slight_smile:


Eating considerably less than you should is always bad for you, and any so called benefits go away once you start eating healthy amounts of food, and is seriously outweighed by all of the downsides of not eating/not eating much. One long term effect of self starvation is that your body will try and hold onto more fat just in case food becomes scarce again/you intentionally don’t feed yourself, which essentially changes your body type if you starve yourself enough. Just eat healthy foods in healthy amounts and excercise a healthy amount, and only turn to drastic measures like liposuction surgery if these healthy methods aren’t enough to keep you out of the obese range. I’m guessing your not obese though, so surgery is not nescessary (unless your (M.D.) doctor says otherwise).
Tl;Dr fasting bad, eating and excercising healthy amounts and types good.


Do you have any scientific studies to back up those claims about fasting? There are plenty of studies that show the benefits of fasting when done safely and correctly. The human body is meant to go through periods of feast and famine and thrives on it.

The starvation/diet effect you mention only applies to long term reductions in calories, that’s why diets typically don’t work. You lose a lot of weight in the first few weeks, but then your body adjusts your metabolism and tries to hold onto more fat and you lose those benefits. This doesn’t apply to short-term fasts though. You’re back to normal levels of eating in less than a week and your body doesn’t adjust your metabolism or fat storage.

Benefits of fasting all shown by various studies:

  1. Fat burning.
  2. Promotes secretion of Human Growth Hormone, helps build muscle mass.
  3. Normalizes insulin sensitivity.
  4. Lowers cholesterol and blood pressure levels.
  5. Improves cognitive function and memory.
  6. Restores the immune system and reduces inflammation.
  7. Breaks down old/unneeded cells and helps prevent cancer.
  8. May slow down aging. Not proven in humans yet, but when intermittent fasts were performed on rats, they aged slower.

And these benefits are shown to last for months after the fast is done.


Got to agree. A lot of the so called facts about “starvation mode” never hold up to scientific scrutiny. Intermittent fasting has a weight of research behind it and although I’ve never fasted (intentionally), it clearly has a net positive effect on holistic health


Actually, “starvation mode” is a very real thing and easily observed … but it has to be actual starvation before you see it have the most damaging effects. It’s really easy to observe in fact – just ask any five women who have done low-calorie diets how fast the weight came back, whether they gained a bit more after, and whether it hurt them in the long run in their opinion. You’re likely to get 3 of the five having bad results, and probably worse. The same thing sort of applies to men, but in modern America, men don’t normally go on that kind of a dangerous diet unless they’re already fat and want to lose weight, or they’re entering the military.

Intermittent fasting, or even regular fasting, can have positive effects, assuming that the person doing it doesn’t binge in between.


Fasting Mimicking Diet seems like a really stupid idea. Fasting and intermittent fasting avoid the problems associated with ‘starving’ specifically by ‘not eating food’(carbs). Problems with starving come specifically from eating restricted calories.

Additionally the main benefits from fasting and IF come from forcing fat utilization. If you’re eating food, your providing blood glucose and then insulin, removing any benefit. If you’re sticking to IF while doing this then the only thing you gain is hunger and discomfort (and later happiness when you stop torturing yourself).

If you do not have adequate fat, fasting and calorie restriction causes gluconeogenesis or loss of muscle mass, especially without exercise. If you’re not overweight I would recommend not reducing calories.

I did a quick google and it seems mostly bs but I found this quote hilarious “[FMD has some] of the many health benefits of intermittent fasting”. If you’re already fasting … ¯\(ツ)


Seems like this is a topic for @MentalNomad.


I’m afraid that’s almost certainly wishful thinking… you’re unlikely to get the benefits of a fast by eating! The “Fasting Mimicking Diet” sounds more like short-term Caloric Restriction, just to a more severe degree. Maybe it’s Short-Term Caloric Super-Restriction.

There are a variety of potential upsides to doing it, especially if you’re coming from a diet of excess, but that’s way too many calories to pretend it’s going to have the same benefits as a fast… and many of the effects of traditional caloric restriction take a long time to realize, so this kind of 3-day caloric super-restriction may or may not get some of those benefits.

I don’t think Soylent is great for this. Generally speaking, these kinds of diets recommend foods that are very nutrient-dense - avoiding all empty calories. Reducing your Soylent also reduces the vitamins/minerals, in equal proportion. If doing this, I’d consider following the food recommendations for Calorie Restriction… then again, CR is a long-term thing. Since you’re only doing it for a few days, there’s almost no risk of any real issues from the reduced nutrients, so I don’t think it’s a big deal.

Most important, if you really want to do this sort of 3-day crash diet, and Soylent is working well for you, well, go ahead… you’re not going to suffer some sort of severe nutrient deficiency in three days unless you were already deficient going into it, for some reason.

In my experience, fasting is eaiser than eating a small amount like this. Even the small calorie hit from a single bottle of Soylent would likely be enough to trigger my metabolism and hunger drive. As long as I’m drinking enough water I find fasting easier than pretty much any level of calorie restriction by the time the second or third day rolls around. (A 20% calorie restiction for one day is easy, but I get really hungry if I keep that up for a second or third day… hungrier than if I were fasting.)

Absolutist statements are always wrong.

If your goal is fat loss, then that’s true. If your goal is better health, then that’s not true.

A little excess fat on the body is actually not highly correlated with health problems for individuals who are otherwise fit and healthy… for such people, losing a few pounds of fat is unlikely to have any health benefits, whatsoever. A little fat can even be a health buffer in the event that they experience an adverse event in the future, such as a disease which makes it difficult to eat (or a famine.)

However, they can still experience benefits from protein restriction (such as cellular cleanup during autophagy) and from carb restriction (such as improved glucose handling and insulin sensitivity). And they can lose a little fat, too.

The catch is that getting these benefits through partial restriction takes longer than achieving them through fasting… and given that we know that certain benefits of fasting don’t peak until 72 hours or more, it’s unlikely that you’re achieving them with a partial restriction in three days, even a partical restriction as severe as the one described here. (IMHO, that is. I’m speculating. I haven’t looked for and read research specifically on the Fasiting Mimicking Diet, but I’m fairly well-versed on fasting, PSMF, IF, CR, and health/nutrition.)


Thanks for chiming in MentalNomad, some good thoughts and points there, though I should clarify that the FMD is 4-6 days, not just 3 days. According to the studies I’ve seen and stories from people who continually measured their blood ketones and glucose throughout the FMD, this level of calorie restriction for this period of time is long enough to enter ketosis and start triggering those various fasting benefits.

As far as the nutrient side of it, doesn’t your body require proportionally fewer vitamins/minerals if you’re consuming fewer calories? Regardless of whether a person normally consumes 2,500 calories a day or 1,500 a day, if they drank 100% Soylent for either of those diets, they’d be covered for what their body used on a daily basis.