Weight Loss Calculator, Including Glycogen and Alcohol Processing.

Created for use, not for selling adverts!

Me and a bike
An exercise calculator that is deliberately detailed as oversimplification can be misleading and confusing.

Is this one of the most sophisticated weight loss calculators on the internet?

The internet is full of calculators and articles about weight loss and exercise, so I thought that I would add another one, but this one shows weight gain and loss in intervals as short as 15 minutes!

Initially I created this calculator as the basis for an article on the software engineering principles of SOLID, but it has taken on a bit of a life of its own and I have given it its own page.

Below is a calculator that allows you to specify food eaten and exercise performed and at what time of the day, it then calculates the effect on body weight in small time intervals, between 15 and 60 minutes for 1 to 5 days.

At first glance this sounds like absurd overkill but actually it makes a great deal of sense.

Glycogen levels in particular appear to be an area that benefit from this level of detail, especially when dieting or increasing exercise.

In general the longer that the calculation periods become the more that the calculator simply becomes "eat as much as you need and no more".

As might be expected the calculator is a simplified version of the body and exercise, many assumptions are made, default values used and handling of special cases limited.

For example ketosis is not supported but there is a reasonable recognition of glycogen depletion and an upper glycogen storage limit, transition of food from the stomach to the intestine is simplified and each food item is processed with some but no full consideration of the impact of other food items.

Clearly if you are an expert on human physiology the accuracy of these simulations can be ripped apart especially when you look at short time periods. In the real world an energy gel taken alone is digested differently from one taken with a pork chop, but getting this exactly right isn't critical.

Personally I find that this calculator has too many questions and a too big an answer to work well on lower screen resolutions. I wuld suggest that if you are going to spend time using it a tablet, laptop or pc would give a better experience.

I have tried it on an iPhone 5, probably the smallest screen in common use and it works, just about.

Exercise And Nutrition Details


My Details
Age (years)
Height (cm)
Weight (kg)
Basal Metabolic Rate
Background Miles Walked (daily)
Add To The Food To Be Eaten
Eat Time :
Standard Meals    
Tins & Pies    
Fruit & Veg    
Advanced Food Editor
List Of Food To Be Eaten

Cycling Fitness And Equipment Cycling Mileage
Max Speed For 5 Minutes Start Ride   :
Average Speed For A 60 Minute Ride Riding Time (Minutes)
Bike Type Average Ride Speed (mph)
Riding Position Average Ride Power (watts)
Bike & Luggage Weight (kg)

Running Fitness Running Mileage
Best Time For 1 Mile Start Run   :
Best Time For 5K Running Time (Minutes)
Average Run Speed (mph)
In order to keep the input screens a reasonable size exercise has been limited to running and cycling, please let me know if there are other exercises that you would like to see.
Exercise To Be Undertaken

Calculator Options
Calculation Rate
Calculation Days
Muscular Efficiency
Brief Output
Hide Night
Save Details
Confirm Password
Save Details
Recover Details
Saved As Reference
Recover Details


Last Run Time:

This is an example of the results of the calculation.







100:0069.000140040015000/049Eat Fried Breakfast(1)
68.981138539614840/049Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
68.918134138314370/049Cycling(1) at 119 watts, used fat/glycogen 55kc/47kc
100:1568.898132637914210/048Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
68.835128336613740/048Cycling(1) at 119 watts, used fat/glycogen 55kc/47kc
100:3068.864130537313980/048Digest Fried Breakfast(1) converted 6.3g of carbs to 24kc of glycogen
68.842128836813800/048Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
68.779124435613330/048Cycling(1) at 118 watts, used fat/glycogen 55kc/47kc
100:4568.808126736213570/048Digest Fried Breakfast(1) converted 6.3g of carbs to 24kc of glycogen
68.807126536113550/048Digest Fried Breakfast(1) converted 1.5g of fat to 14kc or 1.7g of body fat
68.784124735613360/047Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
68.721120334412890/047Cycling(1) at 118 watts, used fat/glycogen 55kc/47kc
68.721120334412890/047Cycling(1) completed, 188kc of glycogen used and 220kc fat used, totalling 408kc
101:0068.749122535013130/047Digest Fried Breakfast(1) converted 6.3g of carbs to 24kc of glycogen
68.749122435013110/047Digest Fried Breakfast(1) converted 1.5g of fat to 14kc or 1.7g of body fat
68.725120634412920/047Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
101:1568.754122835113160/047Digest Fried Breakfast(1) converted 6.3g of carbs to 24kc of glycogen
68.752122635013140/048Digest Fried Breakfast(1) absorbed 1.5g of protein
68.754122635013140/048Digest Fried Breakfast(1) converted 1.5g of fat to 14kc or 1.7g of body fat
68.730120834512940/048Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
101:3068.759123035213180/048Digest Fried Breakfast(1) converted 6.3g of carbs to 24kc of glycogen
68.757122935113160/049Digest Fried Breakfast(1) absorbed 1.5g of protein
68.758122935113160/049Digest Fried Breakfast(1) converted 1.5g of fat to 14kc or 1.7g of body fat
68.735121034612970/048Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
101:4568.760123035113180/048Digest Fried Breakfast(1) converted 5.6g of carbs to 21kc of glycogen
68.758122835113160/050Digest Fried Breakfast(1) absorbed 1.5g of protein
68.739121334713000/049Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
102:0068.739121334713000/051Digest Fried Breakfast(1) absorbed 1.5g of protein
68.720119834212840/050Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
102:1568.720119834212840/052Digest Fried Breakfast(1) absorbed 1.5g of protein
68.700118333812680/051Basal 16kc fat/glycogen 0kc/16kc, protein 0.6g
ExCalc Version:

It's Close Enough Most Of The Time.

me in the garden

Even if I wanted to develop a 100% accurate simulation of the digestive system and the effects of exercise it would be too complicated to use requiring hundreds of user specific parameters that the user has no way of knowing.

Anyway this isn't possible as once you get beyond very broad statements there is little agreement on many of the details.

Notes On The Exercise Calculator

The calculator is an approximation not a 100% accurate simulation but it is intended to be useful when fed with realistic inputs.

The simulation is intended for people who are looking for a general overview on food, exercise and bodyweight rather than elite level athletes looking for a tool to use as part of a training plan or someone looking for something that is so accurate that it can be relied upon to lose weight.

Probably the first thing that you will notice is that the calculator uses blood glucose and glycogen interchangeably, this is clearly inaccurate but only has any real effects if you set up a calculation that deliberately goes into glycogen depletion and exercises in that state.

On the same theme, ketosis is an area that the calculator simply pretends does not exist, the calculator starts off with around 1,400kc of glycogen and has a maximum period of 5 days, so ketosis could be triggered. So if in the real world you do a week of a no carbs diet and then compare your results with the calculator there will be little similarity.

But how many people are going to want to do this?

Glycogen on the other hand is processed with a reasonable degree of reality, there is maximum capacity of around 1,800kc and when exhausted the specified exercises are changed to a reduced intensity.

When alcohol is consumed it enters the blood stream very quickly, the exact speed being affected by the type and quantity of food recently eaten. The calculator then shows the blood alcohol numbers rise and fall (the mg/100m values) but the energy (kc) derived from the alcohol rises and falls out of sync with this.

This is correct as the energy derived from alcohol comes as it is processed and this takes time. Note also that alcohol derived calories are used in preference to either glycogen or fat and that the presence of alcohol in the blood stream slows the processing of other food items.

The exact balance of fat and glycogen used during exercise is varied by collecting an approximation of the user's fitness level and the intensity of the exercise.

Again this is an approximation, if you do a ride on a TT bike wearing a skinsuit you will use less energy for a given speed, but do you want to answer all the questions necessary to calculate this. Especially as today's wind was at 8.5mph not the 10.5mph that you thought it was, so the results are wrong anyway.

Energy expended is based on a 25% bodily efficiency.

There are two planned to-dos
  1. Add in support for ketosis.
  2. Add in post exercise recovery.


There are some quirks in this calculator, some are almost inevitable and some may be addressed.

When You First "See This Bit", It Looks Dumb.

"This is silly" so the whole calculator must be useless!

There are some things that the calculator does that appear odd, don't really matter and are necessary if you want to produce a meaningful result.

Sequential food processing.

The way that the calculator reports things make it seem like there is sequential food processing instead of the reality where all the food is mixed up as chyme and chocolate bar 1 and chocolate bar 2 are indistinguishable.

But reporting things as one lump makes reporting on the energy derived from that "extra chocolate bar at lunch" much harder to see.

Background Walking

The calculator has the concept of background walking, this is walking that is not done as a specific exercise but takes place during the day as and when, the walk to the bus or around the factory etc.

The calculator reports this by breaking up the miles walked evenly across the day and reports it even when an activity such as running or cycling takes place. This looks silly but there isn't an obviously preferable way to display it.

Other Sites Have Different Views

Internet flame wars, no thanks.

"My Favourite Site" Gives Different Results.

The internet has sites that say completely different things to you and your results.

There are a lot of health and exercise web sites and many of them will have statements and possibly calculators that won't sit well with the results that this calculator produces.

I am very happy to discuss areas where the calculator could be improved or is actually wrong.

What I don't intend to do is to try and reconcile my results with someone's favourite site that says something like ...cycling typically uses 40 calories per mile... without any supporting arguments.

Many web sites want to be concise so pick averages that seem reasonable to the author and are typical of the expected readership, but without knowing these assumption the articles can be hard to fully understand if you come across them as a result of a web search. If your search gives you a number of sites with the same assumptions then you can end up with a different impression to mine.

What I mean by this is that if you go to a body building site then don't expect the discussion to be about the nutritional needs of an Ironman triathlete and the triathlete's site won't have much to say about the best protein powder to build muscle and minimize fat.

Of course some web sites exist only to post advertising links and simply cut and paste text without any real understanding or interest in the subject. In order to appear higher in search results it may actually be advantageous to have contentious content, you can get your site mentioned on other sites with thing like xyz is saying ..... and is wrong because.