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Calorie Count or How Far Can I Go?

Vic Denwood provides an overview of how you might use calorie counting to manage your weight.

I have a brand new exercise bike. It is very clever and tells me how fast I am pedalling, how far I have gone, power output, duration, pulse rate, and how many calories I have used. It was this last reading that has caused me a problem, since it was showing that after a 10 minute session at 100 watts effort I had used about 250 calories

At first I trusted the computer - don't we all? However after my daughter bought her own exercise bike she commented that I must be working incredibly hard because she was getting a report of 30 calories used in 20 minutes activity. This started me thinking, if I use 250 calories in 10 minutes, then that is the same as 1500 calories per hour! Even Polar Explorers dragging sledges, and channel swimmers do not use calories at that rate. There was something wrong. I trained in the RAF as an electrical engineer, so I know all about Joules and Calories. So I did some sums for myself:

If I work at rate of 100 watts for 10 minutes then that is:

  • 100 x 60 x 10 = 64,000 Joules. (1 Joule is 1 Watt for 1 Second)

To convert to calories DIVIDE the number of Joules by 4.184. In this case for ease I divided by 4 and got 15,000 calories. However since all the food ratings use Kilo Calories (Kcals) then my computer should have shown about 15 Kcals used.

What has happened is that my computer has been incorrectly programmed and is MULTIPLYING the number of Joules by 4 instead of dividing by 4; accordingly, it is a factor of 16 times out in its result. I have written to the manufacturer pointing this out; they agree the problem, and have compensated me for my trouble, and informing them of the hitch.

An Interesting Train of Thought

In my 10 minute session, at a pedal rate of 60 rpm, I was working at 100 watts, and achieving 20 Km per hour speed, and actually used 15 Kcals. So if I carried on for an hour, I would have used 90 Kcals and covered 20 Km. This made me start to realise just how efficient the body is in using its food, and how much exercise would be needed to burn up the calories in food.

How Far can I Go?

Remember the "baseline" for me is: 100 watts for 1Hr uses 90 Kcals to achieve a 20 Km distance. So I looked around the house for some common foods and also the NHS website[1] for a food calorie listing, and produced the following results table.

Food Type Quantity (Gms) Kcals Endurance (Mins) Distance (KM) Comment
Coffee Whitener 6.5 26 17 5.6 28 servings/week
Non-Diet Cola 100 86 57 19  
Potato Crisps 40 284 190 64 2 Packs/week
Porridge Oats 100 375 250 83  
Weetabix 100 342 230 76  
Chocolate Digestive 1 80 53 17 14/week
Mini Pork Pie 1 200 133 44 6/week
Milk 500 ml 244 160 53 3.5 litres/week
Flour 100 330 220 73  
Bread 1 Slice 144 96 32 12 slices/week
Bread Roll 1 140 96 32 3/week
Butter 100 737 490 160 200g/week
Lard 100 900 600 200  
Rapeseed Oil 100 900 600 200 That's 5000+ mpg
Peanuts 25 147 100 22  
Mars Bar 100 446 300 66  
Beer 500 310 200 44  
Red Wine 375 255 170 38  

Table 1 - Sample Food Listing

What did I Save?

When I retired in 2011 to look after my wife, my activity level dropped and my weight gradually crept up. This was not helped by regular intake of Chocolate Digestive biscuits each afternoon with a cup of tea, and an evening snack of a mini pork pie (or two), or a crisp sandwich, when my wife was fast asleep. By the beginning of 2014 I was 15st 7lbs and distinctly obese. So I decided to take matters in hand and stopped coffee whitener, my snacks, and cut out all buttered bread, cake, and biscuits.

Food Type Quantity (Gms) Kcals Weekly Consumption Calories Saved
Coffee Whitener 6.5 26 28 Servings 730
Potato Crisps 40 284 2 Packs 568
Chocolate Digestive 1 80 14 1120
Mini Pork Pie 1 200 6
Milk 500 ml 244 3.5L
Bread 1 Slice 144 12
Bread Roll 1 140 3
Butter 100 737 200g
      Total 8966

Table 2 – Drop Outs

I am so astounded!

I have only just produced this table as part of writing this article, and I have never done this analysis before. We are told that an average man needs 2000 Calories per day. From the table above you can see that I have saved 4 days worth of calories per week. I was effectively eating 11 days food each week, no wonder my weight crept up!

Since stopping the foodstuffs above, and adding reasonable light daily work outs on an exercise bike, I am now, 10 months later, weighing 11st 6lbs.

Inner Stores

Table 1 shows that basic fats, such as lard, and edible oils all have the same high calorie count (9000 per Kg). That is why Orcas, Polar Bears, and Eskimos love to eat Seals - lots of blubber to keep them warm. That fat that is so sought after is also the same fat, in calorie terms, as resides in us as a food store and energy reserve. So from Table 1 we see that 100gm of Lard or Oil will take me 200 Km - so to lose 1Kg by exercise alone I would have to cycle for 100 hours and 2000 Km. From this it becomes really obvious that exercise alone cannot get your weight down.

As a matter of interest, the planners for a recent polar trekking expedition worked out that the explorers needed an energy budget of 8000 Calories per day. This is virtually impossible to achieve with normal rations - eating 1Kg of pure fat a day is not viable due to the appalling effect it would have on the lower gut! So their solution was for the explorers to build up body fat reserves prior to the expedition, eat highly nutritional balanced rations when on the ice, and let the body draw on the inner fat reserve as necessary to make up any energy deficit.

What Worked for Me?

I am 68 years old, and "traditionally" it is difficult for us to lose weight. However I seem to have found a solution that worked for me.

A possible suggestion for you:

  1. Make your own equivalent of Table 2 for food items you can relatively easily give up, and those you really should. Bread & Butter together with coffee whitener would be a good easy starter for a 4000 Calorie per week reduction, add Biscuits & Crisps and you have a further 1000 Calorie reduction.
  2. Try and stay away from foods with thick creamy sauces made with flour and butter – potentially high calorie in its own right never mind the food it is accompanying.
  3. Look out for low calorie, low fat foods, and diet soft drinks, when you go shopping.
  4. If you can, add some exercise to your daily routine. I was fortunate to be able to buy and exercise bike and do two 10 minute sessions most days, one in the morning and the other in the evening. Do whatever you can and whatever suites your circumstances.
  5. If you have the urge to snack in the evening – like I still do. Then a glass of plain water helps – don't add cordial flavourings, which adds calories, and for me makes me still want to snack – just plain cold water seems to do the trick. If that doesn't work – go to bed!

Diabetes 2 - Vic 0

Despite annual medical tests whilst in the RAF, it was not until a year after I retired that it was discovered, by accident, that I had Type 2 diabetes. This has been controlled by tablets ever since. And since then, my tablets have been increased every 3 years or so.

In January my HbA1c was 69. This means that I was close but not quite down to the level that the doctor would have liked. By June, having stopped most of my snacks in the evening, and lost 1 stone in weight it was 54 - the doctor approved but still wanted better. So I cut out all the stuff in Table 2 and started a moderate exercise regime. This week, in September, I am a further 2 stone lighter and my HbA1c is now 39. This is a massive improvement, effectively, at that level; I am very low borderline diabetic, or even possibly disease free.


It is now early November, now 11st 10lb. I have seen the Doc about my blood levels at last. He is very pleased with the weight lost, but my blood levels are too good! So he has reduced my tablets by half, and will be taking another blood test in January to see how things are. I gave him a copy of Table 2, and the NHS website reference which seemed to interest him greatly.


  1. Calorie Checker [www] available from [Accessed 10/11/2014]

Page Reference

If you quote information from this page in your work then the reference for this page is:

  • DENWOOD, V. (2014) Calorie Count or How Far Can I Go? [WWW] Available from: [Accessed

About the Author

Vic Denwood is a retired RAF Engineer and IBM Business Analyst. 

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