I doubt they were burning all that food so they were probably consuming it with increased physical activity and consuming more meat in their diets than the typical Harnic.
1,500 calories a day is to low IMO basically just moping or sitting around the house doing little physical activity. Medieval life was more physically intensive and demanding, particularly for the farmers and laborers.
First thing I found I'm sure someone can find something else slightly different:http://recipes.howstuffworks.com/question457.htmThe number of calories the body consumes in a day is different for every person. You may notice on the nutritional labels of the foods you buy that the "percent daily values" are based on a 2,000 calorie diet -- 2,000 calories is a rough average of what people eat in a day
. But your body might need more or less than 2,000. Height, weight, gender, age and activity level all affect your caloric needs
. There are three main factors involved in calculating how many calories your body needs per day
basal metabolic rate
thermic effect of food
Your basal metabolic rate (BMR) is the amount of energy your body needs to function at rest. This accounts for about 60 to 70 percent of calories burned in a day and includes the energy required to keep the heart beating, the lungs breathing, the eyelids blinking and the body temperature stabilized. In general, men have a higher BMR than women. One of the most accurate methods of estimating your basal metabolic rate is the Harris-Benedict formula
Adult male: 66 + (6.3 x body weight in lbs.) + (12.9 x height in inches) - (6.8 x age in years)
Adult female: 655 + (4.3 x weight in lbs.) + (4.7 x height in inches) - (4.7 x age in years)
Average Harnic Male 68" 153#, average Harnic Woman 66" Light Frame 130#.
"Adult Male Roughly" 1,035 + 850 = 1,800 - 1,900 base range before subtracting years at 70 per decade so say 1,700 at age 20 before factoring caloric burning activity
. Adult Woman 1,200 + 300 = 1,500 base range subtracting "50" per decade say 1,400 at age 20 before factoring in caloric burning ativity
.The second factor in the equation, physical activity, consumes the next highest number of calories
. Physical activity includes everything from making your bed in the morning to jogging. Walking, lifting, bending and just generally moving around burns calories, but the number of calories you burn in any given activity depends on your body weight.
The thermic effect of food is the final addition to the number of calories your body burns. This is the amount of energy your body uses to digest the food you eat -- it takes energy to break food down to its basic elements in order to be used by the body. To calculate the number of calories you expend in this process, multiply the total number of calories you eat in a day by 0.10, or 10 percen
t. If you need some help determining how many calories you eat in a day:http://www.nutristrategy.com/activitylist.htm
Calories per hour by weight 130# 155#
Farming, baling hay, cleaning barn 472 563 654 745
Farming, chasing cattle on horseback 236 281 327 372
Farming, feeding horses or cattle 266 317 368 419
Farming, feeding small animals 236 281 327 372
Farming, grooming animals 354 422 490 558
Forestry, ax chopping, fast 1003 1196 1389 1582
Forestry, ax chopping, slow 295 352 409 465
Forestry, carrying logs 649 774 899 1024
Forestry, sawing by hand 413 493 572 651
Forestry, trimming trees 531 633 735 838
Gardening, general 236 281 327 372
General cleaning 207 246 286 326
Backpacking, Hiking with pack 413 493 572 651
Aerobics, general 384 457 531 605
Aerobics, high impact 413 493 572 651
Aerobics, low impact 295 352 409 465
Aerobics, step aerobics 502 598 695 791
Winter activity because lack of modern heating requires more personal calories to maintain body temperature in cooler temperatures. Some resource trade off for heating residence via animals (more winter fodder) and firewood (collecting, chopping, stacking burns a lot of calories although many collected drop wood by hook and crook) doubtful large fires were maintained in the average home due to transfer inefficiencies unless wood was plentiful.
Cross country snow skiing, slow 413 493 572 651
Cross country skiing, moderate 472 563 654 745
Cross country skiing, racing 826 985 1144 1303
Cross country skiing, uphill 974 1161 1348 1536
Cross country skiing, vigorous 531 633 735 838