To help us understand the content of energy

and macronutrients, as well as some micronutrients, in the food we eat, the label of every packaged

food has to carry a standardized nutrition facts panel. For fresh produce and other foods

that do not come pre-packaged, such as bananas or chicken breasts, we can refer to food composition

tables, for example the United States Department of Agriculture’s national nutrient database

for standard reference, which is available online free of charge. Nutrition facts labels indicate the nutrient

content per serving of food. While this has an obvious practical advantage, it can also

be very deceiving because your idea of a serving may largely differ from what the label says.

This bag of cheese balls snacks says it contains 9 grams of fat per serving, however it also

says that a bag contains 9 servings. Now I don’t know about you, but I for one, am

not going to eat nine times out of this bag. In fact, I could very easily eat half of it

right after I open it, so I would be getting 40 grams of fat and 675 calories.

In this course, we’ll express nutrient content as % in weight. The advantage of doing it

this way is that it’s independent of the serving size. So for example, we would say

that these chips have 32% of fat. This means that 32% of each cheese ball is made of fat.

If I eat 100 grams of them, of course I’m getting 32 grams of fat. If I eat 50 grams,

I’m getting 32% of 50, so 16 grams of fat. And if I eat 28 grams, which is what the label

says it’s one serving, then of course I’m getting 32% of 28, 9 grams of fat, like the

label says. This is the percent nutrient composition of

whole wheat bread, and this is the color code we will use throughout the course. Composition

in weight of any food is mostly accounted for by water, digestible carbohydrates, fats,

proteins, and fiber. And alcohol for alcoholic drinks. Micronutrients such as vitamins, minerals

and other phytochemicals are present in smaller amount, and in most cases account for less

than 1% of a food’s weight. As we study the different nutrients, you will learn that

in order to make an appropriate nutritional evaluation of a food, we need more details

about its composition. For example, not only the total amount of fat, but what type of

fat, not only the total amount of protein, but the quality of that protein, and of course,

not only the total amount of carbohydrate, but its composition, for example how much

simple sugar and how much starch. Also fiber content needs to be broken into soluble and

insoluble fiber. But for the time being, let’s just focus on this simple partitioning. As

you can see, 43% of the weight of whole wheat bread is accounted for by water. 34% is carbs,

13% is proteins, 7% is fiber and 3% is lipids. So, how many grams of proteins are there in

100 grams of this bread? Easy, 13% of a 100 is 13, so 13 grams of protein. But a slice

of this bread actually weighs 30 grams. So how many grams of proteins do we have in one

slice of bread? 13% of 30, so 30 divided by 100, times 13, about 4 grams of proteins. Another useful calculation that it’s often

done is looking at how much of the energy of a food comes from the different macronutrients.

This can be useful because it allows us to easily compare a food with the ideal distribution

of macronutrients in our diet, which as you’ll remember, is set in the DRIs. In this calculation,

we consider that water and fiber provide no calories, that carbs and proteins provide

4 calories per gram and that lipids provide 9 calories. For example, this is the percent

nutrient composition of whole milk. As you can see, it’s mostly water, with 4% of carbohydrates,

mostly lactose, 3% of lipids and 3% of proteins. 3% of lipids doesn’t look that much, so

why do we always say it’s better to drink low fat milk? Well, if we look at how many

of the calories from milk come from fat, we find that it’s about half, and that is a

lot. How did we calculate that? If we consider 100 grams of milk, it has 3 grams of proteins

times 4 calories per gram, so 12 calories from proteins; then 3 grams of lipids times

9 calories per gram, so 27 calories from lipids, and then 4 grams of carbs times 4 calories

per gram, so 16 calories from carbs. Water, of course, provides no calories. 12 plus 27

plus 16 is 55 calories. So 100 grams of milk provide 55 calories. 27 of these calories

come from lipids. In percent, this is 27 divided by 55, times a 100, so 49%, which is almost

half. If you consider that milk is a beverage so we can easily drink a lot – one good glass

is 250 grams, so about 8 grams of fats – AND, as we will learn, fat in milk is not of the

best quality, then yes, it is definitely better to go for the reduced fat version if you drink

milk regularly. But now let’s go back to our nutrition facts

label. This is a label for whole milk. The first information we get is the serving size,

which is considered to be one 8 fluid ounces cup. This cup, provides 146 calories, and

71 of these calories come from fat. Again, this is almost half, so the calculation we

made before was correct. A look at the nutrition facts label spares us from having to do our

own calculation every time. This cup provides 8 grams of total fat. The

label also compares this with the daily value for the average adult. These 8 grams of lipids

are 12% of the total amount of lipids an average adult should get every day.

Then, the label specifies how many of these total lipids are saturated lipids. This will

make more sense later in this course when we study the lipids. But I’m sure you know

already that saturated fats in general are not the best for your health, and two thirds

of the lipids in milk are saturated. This is at least in part what I meant before when

I said that fat in milk is not of the best quality. The label also specifies how many

trans fats are in our food, and again, this will all make sense later. Moving on, the

label tells us how much cholesterol and how much sodium are present in our milk. Then,

it shows how many total carbohydrates are in our cup of milk, 13 grams. Now, you have

to be very careful here: the nutrition facts label includes dietary fiber in the total

carbohydrates count, so these are not just the digestible carbs.

I personally think this is very confusing, but that’s how it is. Now in the case of

milk, this is meaningless because milk provides no fiber, and the sugar lactose accounts for

all those 13 grams. But if we were looking at the label of a fiber containing food, then

we would have to subtract the grams of dietary fiber from the grams of total carbs, to find

out how many digestible carbs are in there. Next, we have the total grams of proteins,

8 grams, and the content of some important micronutrients expressed as percent of the

daily value. This cup of milk covers 5% of our average daily need for vitamin A, 28%

of our need for calcium, while it doesn’t contribute to our daily need for vitamin C

or iron. This is the nutrition facts label of whole

wheat bread. The serving size is one slice. It provides 69 calories, 8 of which from fat.

Indeed, there’s only 1 gram of total fat in this slice of bread, with almost no saturated

and trans fat. I say almost because you see that curiously, these 0 grams of saturated

fat cover 1% of the daily value, this is because numbers are rounded, so that 0 is actually

zero point two. No cholesterol. 132 mg of sodium, which is not little. Then 12 grams

of total carbohydrates. 2 of these are fiber, so digestible carbohydrates are actually 12

minus 2, 10 grams. 2 of these are simple sugars, so the remaining eight are starch. We then

have 4 grams of proteins in our slice of bread, and a little calcium and iron. I’m now giving you a little assignment involving

macronutrient calculations and I strongly encourage you to try your hand at it, not

so much because you should do these kind of calculations normally, but because doing it

at least once in your life is the only way to make sure you have fully grasped the concepts

we presented over the last few videos. So, let’s make a simple sandwich with whole

wheat bread, swiss cheese and pork ham. This is the percent nutrient composition of these

three ingredients. For our sandwich, we are using 2 slices of bread, which correspond

to 60 grams, 1 slice of cheese, which is 30 grams, and 2 slices of ham, which is another

30 grams. If I have done a good job explaining over the last couple videos, you should now

be able to calculate these four things: the percent nutrient composition of your actual

sandwich (meaning, what percent of your whole sandwich is made of lipids, proteins, carbs,

water and fiber) how many total calories does your sandwich

provide what percent of this energy comes from lipids,

what from proteins and what from carbs, and how does it compare to the ideal macronutrient

distribution of diet in general After you have done your calculations, you

can find the solution by following the link below.

Bel video!

Ciao! c'è un errore intorno a 4:30. Fai i calcoli considerando il 3% dei lipidi e il 4% di carbo, ma il diagramma a torta segna l' opposto: 4% sui lipidi e il 3% sulle carbo!

Bei video, grazie per questo corso!

grazie!!!

I did it

and it was right

Insoluble proteins are originally included in total carbs on packaging labels? Is it required by law? I don’t see how producers would not subtract it themselves to lower the carb number.

Great

EXCELLENT

the link doesn't work!