Question

1. calculating digestion and absorption rates: the complexity, or density, of a macromolecule impacts the rate that it is digested and absorbed into the body. for example, egg protein takes less than 45 minutes to digest, while beef protein is complex and can take more than 4 hours to digest in the stomach. once a macromolecule has been digested, the small monomers are able to diffuse through the small intestine directly into the bloodstream where they can be used. the following chart outlines the approximate digestion rate and absorption rate of common carbohydrates and proteins

table 1. digestion and absorption rates of carbohydrates and proteins
carbohydrate absorption rate
glucose 60 g/hour
protein absorption rates
egg protein 2.9 g/hour
milk protein 3.5 g/hour
animal protein 10 g/hour
note: fats absorb the slowest and the rate varies greatly based on genetics and overall health, which is why we will only be calculating protein and carbohydrate digestion and absorption rates.
carbohydrate digestion rates
fruit juice 0.25 hr carrots, beets, parsnips, turnips 0.8 hr
watermelon 0.3 hr corn, potatoes 1 hr
oranges, grapes 0.5 hr brown rice, cornmeal, oats, peas, beans 1.5 hrs
apples, peaches, cherries, pears 0.6 hr seeds 2 hrs
tomato, lettuce, celery, spinach 0.7 hr nuts 3 hrs
protein digestion rates
fish 0.5 hr turkey 2.2 hrs
egg 0.75 hr lamb 3 hrs
skim milk 1.5 hrs beef 4 hrs
whole milk 2 hrs pork 4.5 hrs
chicken 2.1 hrs cheese 5 hrs
a. an average human eats the following foods in a day. determine the digestion rate, absorption rate, and total digestion time of each meal using the information from table 1 (remember 1 g = 1 ml). the “snack” has been completed for you as an example.
breakfast 8:00 am
scrambled eggs (60 grams) with cheese (20 g)
orange juice (150 ml)
snack 10:30 am
almonds (40 g) and sunflower seeds (30 g)
lunch 12:00 pm
chicken (100 g) & spinach salad (350 g)
apple juice (200 ml)
dinner 6:00 pm
beef steak (130 g) & baked potato (250 g)
skim milk (200 ml)
dessert 8:30 pm
peach (75 g) and oat cobbler (115 g)
table 2. meal digestion, absorption, and elimination rate
breakfast
carbohydrates
proteins
snack
carbohydrates 70 g (40g + 30g) 3 hrs total 1.17 hrs (70g / 60g)
proteins 0 0 36 hrs 39.17 hrs

Explanation:

Step1: Determine carbohydrate and protein amounts in breakfast

Orange - juice is the carbohydrate source in breakfast. It is 150 ml (since 1 g = 1 ml, 150 g). Scrambled eggs (60 g) and cheese (20 g) are protein sources, so protein amount is 60 + 20=80 g.

Step2: Calculate carbohydrate digestion rate

From Table 1, orange - juice digestion rate is 0.5 hours.

Step3: Calculate carbohydrate absorption rate

Carbohydrate absorption rate of glucose is 60 g/hour. For 150 g of orange - juice (assumed similar to glucose for absorption rate here), absorption time $t=\frac{150}{60}=2.5$ hours.

Step4: Calculate protein digestion rate

Egg digestion rate is 0.75 hours and cheese digestion rate is 5 hours. We need to consider the combined effect. But if we assume we calculate based on the dominant protein source (more weight), for 80 g of protein (60 g eggs and 20 g cheese), we first consider eggs.

Step5: Calculate protein absorption rate

Egg protein absorption rate is 2.9 g/hour. For 60 g of egg protein, absorption time $t_1=\frac{60}{2.9}\approx20.69$ hours, for 20 g of cheese protein (animal - like protein with 10 g/hour absorption rate), absorption time $t_2=\frac{20}{10} = 2$ hours. Total protein absorption time considering both is more complex, but if we consider them separately and sum approximately, it is around 20.69+2 = 22.69 hours.

Step6: Calculate total digestion time

Total digestion time for breakfast is the maximum of the digestion times of carbohydrates and proteins. For carbohydrates, digestion time is 0.5 hours and for proteins (dominated by eggs here) is 0.75 hours. So total digestion time is 0.75 hours.

Answer:

Meal	Total Amount (g)	Digestion Rate	Absorption Rate	Time in Large Intestine	Total Time (hours)
Breakfast - Proteins	80	0.75 hours	22.69 hours	36 hours	36+0.75 + 22.69=59.44 hours

(Note: The absorption and digestion calculations for proteins considering multiple sources can be refined further, and this is a simplified approach based on the given data in the tables).

We can follow the same process for lunch, dinner and dessert to fill out the entire Table 2. For example, for lunch:

Step1: Determine carbohydrate and protein amounts in lunch

Chicken (100 g) is protein, spinach salad (350 g) has negligible protein compared to chicken here, and apple - juice (200 g) is carbohydrate. So protein amount is 100 g and carbohydrate amount is 200 g.

Step2: Calculate carbohydrate digestion rate

Apple - juice digestion rate is 0.6 hours from Table 1.

Step3: Calculate carbohydrate absorption rate

For 200 g of apple - juice, absorption time $t=\frac{200}{60}\approx3.33$ hours.

Step4: Calculate protein digestion rate

Chicken digestion rate is 2.1 hours.

Step5: Calculate protein absorption rate

Chicken is an animal protein with absorption rate 10 g/hour. For 100 g of chicken protein, absorption time $t=\frac{100}{10}=10$ hours.

Step6: Calculate total digestion time

Total digestion time for lunch is 2.1 hours (since protein digestion time of chicken is longer than carbohydrate digestion time of apple - juice).

Meal	Total Amount (g)	Digestion Rate	Absorption Rate	Time in Large Intestine	Total Time (hours)
Lunch - Proteins	100	2.1 hours	10 hours	36 hours	36+2.1+10 = 48.1 hours

And so on for dinner and dessert.