Optimal parameters when doing soylent-exclusive weight loss?

I’m currently doing a Soylent-only diet (Rosa Labs version for the last ~3.5 months) mainly to massively simplify my food needs. It’s had a side effect of losing weight (~25 pounds so far), an effect I figured would happen, but hadn’t been trying to optimize for. Since I’m only consuming soylent, it’s made me wonder whether we (as a community) know (or at least think we know) what the ‘optimal’ parameters are when doing a soylent-only diet and targeting weight loss as the primary goal.


  • Soylent will be the only food consumed
  • The same amount of soylent will be consumed each day
  • The same schedule of soylent consumption will be used each day (only varying as required by scheduling issues)
  • There is no difficulty for the user to maintain this diet
  • There is a significant amount of weight to lose (~100 lbs, for instance)


  • Type of soylent?
    • Keto? Regular? Other?
  • Calorie target?
    • Function of BMR? Or always some fixed value like 1200?
  • Consumption pattern?
    • Intermediate fasting approach like only eating between noon and 8pm?
    • Smaller meals spread throughout the day?
    • Other?
  • Rate of weight loss?
    • Is there a maximum rate that’s “safe”?


  1. Maximum preservation of lean muscle tissue without requiring any particular sets of exercise
  • Strength training may help, for instance, but shouldn’t be required as part of the recommendation
  1. Most body-friendly rate of weight loss
  • For instance, if losing over a particular rate causes health problems, then that should be noted

Secondary (less important) goals

  1. Simple to prepare (more steps or external ingredients to add mean more complexity)
  2. Less expensive

Current guesses (please give feedback/corrections!)

  1. Keto soylent is better than regular soylent for muscle tissue preservation
  2. Keto soylent is better than regular soylent for speed of weight loss
  3. Consuming soylent via intermediate fasting is better than spread throughout the day
  4. Daily caloric total shouldn’t go below 1000 calories
  5. Daily caloric deficit shouldn’t exceed 1500 calories (very unsure of this)

Thanks, everyone!

I am certainly no expert, but I was under the impression that preservation of muscle tissue generally requires such exercise.

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Yeah, I can certainly expect the answer to include “you’re going to lose muscle tissue if you don’t include strength training”, but the question is more whether one approach (for instance, keto) would “suck less” than another (for instance, ‘regular’ Soylent) in this regard.

There may be no difference at all, and it’s a matter of “you will lose muscle tissue at the same rate regardless of nutrition / calorie level / protein / etc” but at the moment I’m guessing that keto would lose muscle tissue less-fast than non. Would love to hear if that’s wrong, of course. :smile:

Given that some are concerned with the reduction in protein made with 1.4, I would not be surprised at all if keto were a little better in that regard… especially considering that suggested protein intake is supposed to be based off of body weight, and “significant weight loss” would suggest significant body weight.

I myself am trying to lose fat AND build some muscle to help with that (I don’t want to have to eat like a bird after losing the weight), so I add protein to my 1.4.

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Most of what you have said is correct to the best of my knowledge.
Disclaimer: I’m an inexperienced teenager, don’t trust me.

Keto – Since health is obveously a priority for you, I would advise against keto soylent. There is some evidence that cutting carbs leads to faster weight loss than cutting fat, but people are rarely advised to intentionally push their bodies into ketosis. Official soylent has a very high percentage of it’s calories coming from fat already, so I would not advise consuming less carbs than you get from official soylent.

Muscle – For muscle preservation, high protein has helped myself and my family, but that is purely anecdotal. 150% RDI of protein (the amount in official soylent) was enough for me to gain about a pound of muscle even while losing over 2 pounds of fat. I exercise about 30 minutes a day, 5 days a week, at moderate intensity. If you exercise more (or if you are a child and are still growing) you may need slightly more protein.

Rate – The DIY site has a calculator for this. It will tell you exactly how many calories you should have per day to lose at a healthy rate.

So to answer your questions directly: Use regular soylent, eat at intervals you are used to (no reason to screw up your usual clock), and check out the DIY calculator to find how many calories/day will result in quick and healthy weight loss.

From my research on the subject it’s the reduction in calories that’s important in losing weight. Over the long run you will lose the same amount of weight no matter which area you cut from. As long as your body still gets at least the minimums on fat and protein you should be ok.

To that end a person who is not exercising and not trying to change their weight reqires a minimum of 0.8g of protein for every kilogram of body weight. During weight loss your protein requirements will be 2-3x higher. While doubling your protein and still cutting calories won’t help you lose any more weight in the long run than any other macronutrient ratio it will help preserve lean muscle and make a higher percentage of the weight you do lose come from fat. Of course as stated above weight lifting will eliminate the muscle loss all together.

You may want to check out the Soylent calorie guestimator. Keep in mind whatever number it comes up with for you is just an estimation and is meant as a starting point. You may have to play with your calories to get the weight loss you want.

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I found this article that seems relevant and pretty interesting.

The underappreciated role of muscle in health and disease

Extending this notion to the situation of a hypocaloric diet for weight loss, a high percentage of protein in the diet would therefore be expected to effectively repartition nutrient deposition from fat to muscle. Recent reports of improved body composition during weight loss with high-protein, hypocaloric diets support the notion of repartitioning of nutrient intake when protein turnover is stimulated (29). It has yet to be determined whether the same repartitioning occurs when the proportion of protein intake is increased in the circumstance of energy balance (ie, caloric intake = caloric expenditure), but the same rationale should apply.

When I started losing weight on soylent I invested in a Jawbone Up24. Since 99% of the exercise I get is walking, it’s made knowing how many calories I can eat each day a no-brainer.

The only drawback to it is that setting up a custom food for the calorie tracker is buggy as hell. (Probably not as much of an issue if you’re on Soylent or not always mucking with your DIY. Not that I’ve finally stuck with the same recipe for more than five days, or anything.)

I’m pretty sure there are similar apps that’ll work with any smartphone, no need to buy an additional gadget. (If you aren’t a gadget-junky like me.)