The activity should take one class period to complete.
The food Calorie (written with an upper case C) discussed in this guide and
other nutritional references is in reality a kilocalorie, which is 1,000
calories. The daily amount of calories an individual requires is based on
numerous factors. Chief among them are body build, height, gender, age, rate of
metabolism, and level of activity. If an individual is in a very cold climate,
he or she will need more calories to maintain body temperature. Due to these
variations it is necessary to use calorie estimates when making comparisons of
calories consumed versus calories expended.
It is estimated that at the beginning of the Shackleton journey (December 1914)
the explorers had sufficient calories and a variety of foods to meet their
nutritional needs at their level of activity. A year later—when they were
stranded on the ice floes—the demands on them for physical labor increased and
they probably expended more energy then they consumed. Also, the proportion of
their diet that was comprised of carbohydrates was reduced (carbohydrates are
essential for normal metabolic function). At the end of the journey—when the
men basically had no carbohydrates left to eat—they had trouble performing
physical labor. They subsisted on mainly seal, penguin, and seaweed.
A normal diet is approximately 35 percent fat, 10 percent protein, and 55
percent carbohydrates; the explorer's diet at the end was comprised just of
protein and fat. At this point they neither consumed enough calories nor did
they have the variety (carbohydrates and certain vitamins) in their diet
necessary to fulfill basic nutritional needs.
To help students understand what the Antarctic environment is like, have
them read Danger on the Ice on this Web site.
Organize students into groups and distribute the Meals of Endurance
activity sheet. Have students characterize the food listed on the sheet by
placing a check in the appropriate food category (carbohydrate, protein and/or
fat) and rate the meal as being satisfactory or not in terms of variety.
Have students calculate the calories the men consumed in the meal. Have
students multiply this value times three in order to estimate the caloric
intake of the men in one day. Have students evaluate the sufficiency of the
caloric intake of the men in terms of calories expended in a typical day by the
men. Students can make a bar graph where the vertical axis is Kcal and the
horizontal axis is Time (December 1914 to May 1916). Have one column represent
intake of calories and one column represent expenditure of calories. Do the men
ever eat enough calories to sustain their activity levels? How would students
describe the diet at the end of the expedition? Have students look at the three
meals and discuss the trends in the variety and the caloric sufficiency of the
diet the men consumed.
Have students keep a log of all the food they eat in one day. Then have them
categorize it as they did the explorers' meals. Have them add in their own
number of calories consumed to the bar chart. How does their diet compare with
the explorers'? How might the energy required for a teenager living today's
life compare with the calories required of an explorer?
To conclude the lesson, have students comment on the sufficiency and/or
insufficiency of their own diet. Is a one-day analysis enough data on which to
base a valid conclusion? What would students need to do in order to perform a
more meaningful analysis of their diet? Have students discuss how important or
unimportant food is in their day. Is variety important? How would they feel if
they had no bread, fruit, or vegetables for a week? Ask students to imagine
what it would be like to eat the restricted diet the explorers ate in a very
cold and no-electricity environment for months on end.
Features information about how to read the new food label.
Students may be assessed through:
their participation in the activity.
the conclusions they draw about the changes they observed in the
the accuracy of their own nutritional assay.
the quality of their bar graph analysis of the calories consumed vs. the
Research nutritional deficiency diseases such as scurvy or rickets.
Were Shackleton and his crew in danger of suffering from either of these
diseases? Are there areas in the world where deficiency diseases are still
Investigate the changes a body undergoes when it is starving.
For example, female runners who traditionally have little body fat may stop
menstruating. How may this be a survival strategy for the body? Another common
response to starvation is that the body's metabolism slows down significantly.
How is this helpful to survival?