Class Notes: Eating A Healthy Diet PDF

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These notes cover what a healthy diet would supply; ranging all the way from energy to essential nutrients. These notes also explain the functions and benefits of carbohydrates, proteins, lipids, and different vitamins within our bodies. Additionally, a process called hydrogenation is discussed with...

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Class Notes for Eating A Healthy Diet for Spring 2021 STUDENT These are the notes for April 20th Slide 1 Your book says, “Nutrition is the interaction between an organism and its food. Because nearly all nutrients enter through the digestive system, …you are what you eat.” Remember that most of the carbohydrates that you eat are broken down into simple sugars like glucose. Protein is broken down into amino acids. Lipids are broken down into fatty acids and glycerol. Once all the disassembled food has been absorbed, your body must use it or store it. Lipids and carbohydrates can be used immediately after digestion or converted to storage and then used according to need. When we consume more than we need, we store what we don’t use. When we don’t eat enough, the body draws on the stores of fat. We cannot store amino acids. No matter whether you prepare your own food, eat meat or choose a vegetarian or vegan meal prep plan, or enjoy food eaten out or brought in or ordered delivered, to eat well, you need to know what a healthy diet supplies.

Slide 2 A healthy diet supplies: 1. energy: fuel for the cells in the form of glucose. Glucose is broken down by individual cells. As this occurs, the energy stored in the bonds holding the atoms together in the glucose molecule is transferred to molecules of ATP. ATP is our energy currency. Cells spend this currency to carry out all their necessary functions. 2. building blocks: you cannot directly use the oatmeal, orange, banana, or egg. It just does not serve a function in its oatmeal, orange, banana, or egg form, but these foods can be broken down. The protein in the egg white and oatmeal is broken down to amino acids. Fat in the egg yolk is broken down to glycerol and fatty acids. Carbohydrate in the oatmeal, banana and orange is broken into simple sugars such as glucose. The body then uses the glucose, amino acids, fatty acids and glycerol to build the molecules that you do need. 3. essential nutrients: things the body needs but cannot make a. amino acids: you can make 12 but must ingest 8. b. fatty acids: you can make some but not all. You must eat omega 3 and omega 6. c. vitamins: organic molecules. You can make vitamin D, and bacteria in your gut make B6, biotin, and vitamin K, but you have to eat the rest. d. minerals: elements you need. You obviously cannot make elements. Alchemists tried to do this for centuries. 4. a rainbow of fruits and vegetables: the color in fruits and vegetables come from phytochemicals. These plant chemicals slow the aging process, improve memory, fight cancer, raise good cholesterol, lower bad cholesterol, and fight the build-up of plaque in arteries. Different colors protect you in different ways, so you should eat many of the colors of the rainbow each day. We will talk about that in the lecture on Eating a Rainbow of Fruits and Vegetables

Slide 3 Carbohydrates are They should make up about 45% to 65% of your daily calories (you have to figure out the percent of carbs, lipids, and protein that makes you feel and function best). We will use 60% when we talk about carbohydrates. The sugar and starch that were broken down into simple sugars such as glucose are used by brain and muscle. Excess sugar is stored in the liver as glycogen (approximately a 24-hour supply). The rest is stored as fat (so even if you eat little fat, if you eat too many carbs, you will store fat!). We should get most of our carbohydrate calories from complex or super complex carbohydrates because these take longer to digest and do not cause a sugar spike which must be followed by an insulin spike (we have discussed diabetes). As you know from the sugar in pop lab, there is a lot of sugar in pop and juice. You should limit your sugar intake to 30-50 grams/ day in a 2000 calorie diet. Eating a whole orange would give you just 15 grams of sugar and 3 grams of fiber. You would be getting 23g of sugar in an 8-ounce glass of orange juice. Eventually, your body would digest the oatmeal down to just glucose, but it would be released more gradually since the starch has to be broken down into glucose. But in a fast food world, the sugar might come from the sugar in pop or a fruit smoothy. It doesn’t matter if simple sugars come from pop or a fruit smoothy. Sugar is sugar is sugar. Simple table sugar comes from sugar cane or sugar beets. Other sources of simple sugars are honey and fruit. Natural sugars from these plant sources are glucose and fructose. The carbohydrates in our breakfast came from the oatmeal and fruit.

Slide 4 Proteins are They include neurotransmitters, hormones, lymphokines, receptors, enzymes, transport molecules, and muscle fibers. Protein should make up about 10-15% of your daily calories. We will use 10% when we talk about proteins. All proteins are made up of just 20 amino acids. You need to eat protein that contains all 20 amino acids each day, or eat complimentary proteins (table below) because you cannot store amino acids (see slide 2- there is no storage of amino acids). We need to eat all 20 amino acids each day because our body can make 12 of the amino acids, but the other eight are essential amino acids because they

The easiest way to get all 20 amino acids is to eat meat, which is considered a complete protein. A complete protein The chart on the next page shows how to eat complete protein. If you do not eat meat every day, it takes more planning to get all 20 amino acids because very few plant proteins are complete – only soy, quinoa, and wheat germ. The protein in our breakfast came mostly from the egg white, and oatmeal.

You can get complete protein by eating anything in the complete protein column (which should also list quinoa under cereal grains). You can also get complete protein from plants by picking a food from two of the three columns to the right = complimentary proteins  corn and beans for example. It is no surprise that plant diets for centuries have included corn and beans or rice and beans or corn and rice (any combination of two of those three) – those people knew what kept them feeling healthy. You don’t have to know the science behind eating. You just need to pay attention to what makes you feel healthy.

Slide 5 Lipids are essential components of every living cell. Phospholipids and cholesterol make up most of the plasma membrane. Lipids are a stored form of energy. T hey also insulate the body and cushion the organs. Lipids should make up about 20% to 35% of your daily calories. We will use 30% when we talk about total fat. We should eat no more than 65 grams of fat and should try to have most of that be unsaturated fats like olive, canola, safflower, corn, and fish oil. Unsaturated fats are missing hydrogen atoms in their fatty acid tails, are liquid at room temperature, and are mostly plant oils (Slide 7). Saturated fats should be less than 20 grams of our diet each day. Saturated fats have all the possible hydrogen atoms that can bind to carbon, are solid at room temperature, and are mostly animal fats as well as coconut and palm kernel oil (Slide 6). The liver can make many fats from the disassembled ingredients of our last meal, but there are two fats that the liver cannot make and we must eat. When we cannot make something, but we must have it to live, it is called an essential nutrient. There are two lipids that we cannot make from other chemicals in our bodies. These are the omega 3 and omega 6 fatty acids. A teaspoon of canola, olive, or corn oil will supply all of the fatty acids we need.

The fats in our breakfast came mostly from the egg yolk.

Slide 6 Saturated fats should be less than 20 grams of our diet each day, and zero grams would be great). These have all the possible hydrogen atoms that can bind to carbon, are solid at room temperature, and are mostly animal fats as well as coconut and palm kernel oil. Note that carbon (C) bonds (connects) with four other atoms. Most of the carbons in the saturated fat bond with two other carbons atoms and two hydrogen atoms (H). They are saturated with all the hydrogen they can hold. Saturated fats are found in your egg yolk.

Slide 7 Two of the carbons in the unsaturated fat only have one hydrogen bond because the carbons have a double bond. It is the double bond between the carbon atoms that puts the crook in the fatty acid tail. Unsaturated fats are missing hydrogen atoms in their fatty acid tails, are liquid at room temperature, and are mostly plant oils. We can make a liquid oil into a solid like margarine by a process called hydrogenation, which entails Most unsaturated fatty acids are in what is called a cis-configuration, with most hydrogens on the same side of the double bond as seen in this figure. During the hydrogenation process, some of the double bonds remain, but the hydrogen atoms have shifted into a trans-configuration in which one hydrogen is on one side of the double bond and the second hydrogen atom is on the other side of the hydrogen bond. This produces a Trans-fatty acid. There would be no trans fats in the breakfast from last lecture. The saturated fats in egg yolk is not a trans fat. But, for years, manufacturers have been taking corn oil, a healthy plant oil, and turning it into corn oil margarine. We have thought for decades that margarine is better that butter because it is made from corn oil and not animal milk fat. We can make a liquid oil into a solid like margarine by a process called hydrogenation, which entails adding hydrogen back. The advantage to this is that the product has a longer shelf life (doesn’t go rancid). Adding hydrogen to the unsaturated fatty acid tail removes the double bonds and the kink that keeps corn oil liquid and makes the oil solid (hence the corn oil margarine).

It turns out that trans fats are not good for us. Trans fats raise LDL (“bad”) cholesterol, which can increase your risk of heart attack, and lower HDL (“good”) cholesterol, which protects your arteries. Trans fats are found in almost all bakery type items that are sold in stores and in many fried fast foods. Homemade baked goods would not contain trans fats if you cook with oil or butter.

Slide 8 Vitamins are either fat-soluble or water-soluble. Fat-soluble vitamins A, D, E, and K can be stored, while water soluble vitamins B and C are carried out of the body in urine if not used soon. Bacteria in our large intestine make vitamins B6, K and Biotin, while vitamin D is made in the skin exposed to sunlight, but the other 9 vitamins are essential in that we must eat them because we, or our gut bacteria, cannot make them from other chemicals in our bodies. Water-soluble vitamins are not saved in the body. Minerals are essential. We cannot make elements. Carbon, hydrogen, oxygen, and nitrogen make up 96% of our body. Twenty-one other essential elements make up the chemical structure of bones and teeth, contribute to the activity or muscles and nerves, and make up the ions in blood plasma and cell cytoplasm (sodium, potassium)

Slide 9 Nutrients

% of total diet

grams/day Calories/serving Total calories

carbohydrates proteins lipids This is where the 2000 calorie/day diet came from, and why I picked the % total of diet to calculate.

Slide 10 Foods taste good because they contain fat and salt. Foods without salt or fat are sort of bland. You have to think especially about the fats and avoid saturated or trans fats. You also need to be careful about simple sugars found in fruits. In our Eating a Rainbow of Fruits and Vegetables Lecture, we will talk about why eating fruits and vegetables every day is great, but there is a limit of 2-4 fruits for a reason (so much sugar). The pyramid shows 3-5 vegetables a day but you can eat lots more vegetables if they are not packed with carbohydrates or sugar (corn, potatoes, sweet potatoes are an example of that).

More on the pyramid in the next lecture.

Slide 11 So, how do we know how much to eat, especially when much of what we eat is eaten outside of the home, as takeout, or ordered to be delivered, when we don’t have access to nutrition labels? Basic things to know  where fats, sugars, and salt lurk  how much is too much (portion vs serving – next lecture) If you are really concerned about calories, you will have to make an effort to find out the information, or you may find yourself sabotaging your diet with the salad shown on the left. People think salads are healthy, but you can get a bunch of calories very easily in a salad....