Nutrition and cycling
Problem
Nutrition and Cycling printable worksheet part 1 (questions)
Nutrition and Cycling printable worksheet part 2 (cards)
Andy is preparing to cycle from Land's End to John o'Groats.
He will undertake some training rides before the big ride.
These cards contain some information about his training schedule, details about the big ride, and his nutritional needs when he is cycling.
Have a look at the cards and try to make sense of the information.
Then use the information to help you to answer the questions below.
- Andy is planning a short training ride.
He wants to take either bananas or cheap cereal bars with him as on-the-road snacks.
How many bananas would he need to take, to minimise the calorie deficit at the end of his ride? How many cheap cereal bars?
(The calorie deficit is the difference between the calories Andy uses during his cycle ride, and the calories he consumes before and during the ride.)
- After his training rides, Andy is ready to cycle from Land's End to John o'Groats.
How many days will it take?
Work out some of Andy's different options for carrying and consuming on-the-road snacks and drinks.
How can he maximise his consumption while cycling?
Together with his meals, can he consume enough calories each day so that he doesn't lose any weight?
How much of his calorie intake will need to be provided each day through off-the-road snacks?
Possible extension
The Fastest Cyclist follows on from this problem and challenges you to devise a winning cycling and nutrition plan if Andy is racing to reach John o'Groats.
Getting Started
How could you organise the cards?
Are there any pieces of information you haven't used yet?
Are there any cards with useless information?
Could you combine the information on several cards to generate new pieces of information?
Student Solutions
The ride is 38 miles long, which is 38 x 1.61 = 61.18 km. Multiplying by the 100 kJ of enengy used to cycle each kilometer, Andy will use 6118 kJ by cycling. This is converted to kcal using the fact that 1 kcal = 4.19 kJ, so 6188 kJ = 6188 / 4.19 = 1460 kcal.
Since Andy had a big meal of 800 kcal for breakfast he has 1460 - 800 = 660 kcal to make up on the journey.
Even though the ride is short, Anna, Millie, Deena, Lizzie and Izzy wanted to account for the 2500 kcal that Andy needs on top of his exercise requirements. They assumed that Andy burns these 2500 calories at a constant rate during the 24 hour day.
On top of the exercise, during the 2 hour ride Andy needs 2 x 2500 / 24 = 208.3 kcal anyway, which means a total of 1460 + 208.3 = 1668.5 kcal need to be consumed. He has a big meal (800 kcal) for breakfast, so he needs to make up 868.5 kcal on the ride. If he eats 7 bananas, he can make up 840 kcal; if he eats 8 cereal bars, he can make up 800 kcal.
Good! But, didn't Andy only want to limit himself to 250kcal per hour on short trips? What happens here? Jim, from Strathallen, has the answer:
If he wishes to eat bananas, he can eat four of them and consume 480 kcal. If he wants to eat cheap cereal bars, he can eat five of them and consume 500 kcal. So the cereal bars minimises his defecit.
Great - thank you!
Ewan, from King Edward VII School in Sheffield, tackled the second problem with the following method:
The distance from Land's End to John o' Groats is 1407 km, which is 1407 / 1.61 = 874 miles. We know that Andy cycles at 14 mph on multi-day trips so the cycling will take him 874 / 14 = 62.4 hours. Since he wishes to cycle for no more than 7 hours per day, and 62.4 / 7 = 8.9, Andy will take 9 days to complete the trip.
Ewan assumed that Andy would cycle for 7 hours on the first 8 days and have a slightly shorter last day, then worked out the calorie defecit.
In a 7 hour day Andy travels 7 x 14 = 98 miles, which is 98 x 1.61 = 157.78 km. This needs 15778 kJ of energy which is 3766 kcal. Adding the 2500 kcal needed in addition to these calories, Andy requires 6266 kcal per day.
The three really big meals provide 3000 kcal, leaving 3266 kcal from snacks. He can have 350 kcal per hour for 7 hours in on-the-road snacks which is 2450 kcal. This leaves 816 kcal to get from off-the-road snacks.
Another student, Emily, worked out several ways of achieving 2450 kcal (or more!) from snacks and energy drinks:
Andy can carry 3l of energy drink which provides a total of 6 x 190 = 1140 kcal (and he can then refill with water to provide his fluid needs for the rest of the ride).
He can carry
8 bananas = 960 kcal
or 8 energy bars = 1760 kcal
or 16 cheap cereal bars = 1600 kcal
or 24 energy gels = 2640 kcal (though he wouldn't want to consume more than 2450kcal worth)
So he can meet his energy needs with any of these supplemented by energy drink, except bananas.
You might like to think of letting Andy carry combinations of different snacks, he does have 8 pockets after all. See if you can find a way of getting exactly 2450 kcal so that Andy doesn't carry spare food.
Teachers' Resources
Why do this problem?
This problem requires students to make sense of a wealth of information in order to analyse the nutritional needs of a long-distance cyclist. As well as handling data, students will also gain practice in converting units and proportional reasoning.
Possible approach
Arrange the class into twos or threes, and hand out these cards together with this worksheet.
As the activity is a sense-making task, there should be little teacher input, other than to explain that all the information they need to answer the questions is on the cards, and the expectations for justifying and communicating their solutions. While students are working, circulate and make a note of any insights that are worth sharing with the whole group.
Solutions could be presented in a variety of ways:
Groups could prepare a poster
Groups could present their solution to a part of the task to the rest of the class, with other students acting as 'critical friends'
Each group could present their solution to another group
The following key questions or prompts could be offered to groups who are stuck:
How could you organise the cards?
Are there any pieces of information you haven't used yet?
Are there any cards with useless information?
Could you combine the information on several cards to generate new pieces of information?
Possible support
The first question is much less demanding than the second, so you may initially want to hand out this smaller set of cards that just contains the information needed for the first question.
Zin Obelisk could be used to introduce this type of task with easier mathematical content.
Possible extension
The Fastest Cyclist follows on from this problem and challenges students to devise a winning cycling and nutrition plan if Andy is racing to reach John o'Groats.