I put together the previous formulas into one single webpage, the Protein Sparing Modified Fast Calculator. I’ve put my own current numbers into the calculator. Just hit the “Calculate” button to see my numbers. Feel free to try it out with your own numbers and see if it helps you figure out any of this. I don’t see the numbers you enter nor are they stored in any database. All of the calculations are done on your phone web browser or Internet browser (Firefox and Chrome works but Internet Explorer doesn’t).

If you find any errors, please let me know. I tried it with my own numbers and they make sense but I didn’t have a woman’s secret numbers to check.

Here’s a decent introduction to the Protein Sparing Modified Fast (PSMF). I only take exception to one point which is the question of how long you can do a PSMF. They say you can’t do it for an extended period of time. If you continually re-calculate your numbers you should be able to fine tune for maintenance levels. This calculator makes that re-calculation relatively easy. Here’s the results I got for my numbers.

## Your Scale and Metabolism Numbers

Current Weight: 199.8 lbs

Goal Weight: 171.3 lbs

Lbs from Goal Weight at start: 28.5 lbs

Body Fat at start: 25.4%, 50.8 lbs

Lean Body Mass (LBM): 149.0 lbs

Basal Metabolic Rate (BMR): 1818.0 cal/day

Initial Total Daily Energy Expenditure (TDEE): 2500 cal/day

Initial Maximum Fat Loss on Protein Sparing Modified Fast: 0.45 lbs of body fat per day

## Notes

- The Protein Sparing model attempts to conserve Lean Body Mass by leaving your dietary protein amount constant throughout.
- It could be helpful to frequently rerun these numbers based on updated measurements as you progress.
- For the limit on how much fat you can draw from your body per day, see: A limit on the energy transfer rate from the human fat store in hypophagia.
- Body Fat percentage from the Department of Defense Formula or the US Navy Circumference Method
- Total Daily Energy Expenditure from the TDEE Formula by activity level

## Protein Sparing Modified Fast (PSMF) Dietary Macros (per day)

It is very important on the PSMF that you eat at least the macros listed here. If you go below these numbers you risk lowering your metabolism and you actually can’t lose body fat any faster. Attempting to be just above the numbers is OK.

Protein: 119.2 g (476.8 cals)

Carbs: 20 g (80 cals)

Fat: 40.9 g (367.7 cals)

Your total Dietary Calories are 924.4 cals for maximum fat loss.

If you consume 216 g (1943 calories) of fat you will stay at your current weight.At your goal weight you will be able to consume 119.2 grams of Protein, 20 grams of Carbs, and 176.3 grams of Fat.

## Notes

- The protein number is based on KetoGains protein macros.
- The carb number is based on Atkins Induction or ketogenic dietary levels to guarantee ketosis.
- The fat number is determined based on the fastest possible fat loss. This amount of fat in your diet frees up the maximum amount of fat from your body because it does not allow your metabolism to drop.
- For one of many scientific studies of PMSF, see Multidisciplinary treatment of obesity with a protein-sparing modified fast: results in 668 outpatients.

## Can You Fast?

One important question to ask when considering extended fasting is whether or not you have sufficient body fat to fast.

You currently use 2500 cal/day. You have 1575 calories per day available from your body fat for maintenance. You have less calories available from body fat than your daily requirements and may not be able to fast. If you fast, your body may drop your base metabolism, energy expenditures or may consume protein stores. You will be -924 calories short per day

The thermic effect of food contributes somewhere from 5-20% of your current TDEE number so if you are fasting that can reduce your TDEE. Reducing your TDEE by 10% would result in you using 2250 calories per day. Calculating in a 10% Thermic Effect of food still leaves you in a caloric deficit during fasting. The Protein Sparing Modified fast solves this issue by providing the calories needed for the deficit.

## How Much Muscle Can You Gain?

The Maximum Lean Body Mass that you can carry on your frame is 186.5 lbs at your goal of: 15.0% Body Fat. That would be a weight of 214.5 lbs.

## Disclaimer

Use this information at your own risk and with the advice of your medical professional. We are not doctors nor do we pretend to be one on the Internet. We do not take responsibility for errors in these calculations. We do not guarantee that these numbers will work for people at the extremes of the ranges. If you discover an error in calculation, please let us know through email: keto at land-boards dot com.