A calorie is a unit of energy. In nutrition, calories refer to the energy people get from the food and beverage they consume, and the energy they use in physical activity.

Calories are listed in the nutritional information on all food packaging. They are essential for human health. the key is consuming the right amount. Everyone requires different amounts of energy each day, depending on age, sex, size, and activity level.

Most have heard the term "macro" at some point or another. "Macros" are macronutrients. Your body needs these nutrients in larger amounts in order to function properly as "macro" means "large". In addition, all of these nutrients provide your body with energy measured in the form to calories. There are three types of macronutrients: fats, carbohydrates, and proteins.

• Fats contain: 9 cal per gram

• Carbohydrates contain: 4 cal per gram

• Proteins contain: 4 cal per gram

Fats

Fat allows you to store energy, cushion organs, make certain hormones, absorb fat soluble vitamins, and helps with cell membrane integrity. Fats are an essential source of energy as they: care a carrier for the fat soluble vitamins, form part of cell membranes, provide a very concentrated source of energy, provide the starting ingredient for some hormones, and provide essential fatty acids which our body cannot produce. There are three types of fat: trans fat, saturated fat, and unsaturated fat.

• Trans fat should be cut out of the diet. Most trans fat comes from hydrogenating or adding hydrogen molecules to unsaturated fats. This produces a hydrogenated oil. These can be found in margarine, shortening, baked goods, doughs, and fried foods. If you see trans fat on the label it should be avoided.

• Saturated fat does not have any bends, caused by double bonds, in the molecule because it is saturated in hydrogen molecules. In large amounts, saturated fat is known to increase cholesterol levels and can increase your risk for heart disease. Decreasing the amount of saturated fat in your diet can be beneficial. Saturated fat is found mostly in animal sources with high fat contents such as fatty beef, lamb, pork, poultry with skin, lard, cream, butter, full fat cheese, and dairy. It is recommended that you decrease saturated fat intake and lean towards more healthy fats, known as unsaturated fats.

• Unsaturated fat has at least one double bond causing bends in the molecule. These are harder to stack and, therefore, are usually found in a liquid state at room temperature. The number of double bonds allows for the naming of unsaturated fats. Mono unsaturated fats have one double bond while Poly unsaturated fats have multiple or many. Unsaturated fats are known as the healthy fat as they can decrease your risk for heart disease. These healthy fats originate from plant sources such as avocados, nuts and nut butters, seeds, olives, and oils (olive, canola, safflower etc.). They can also be found in animal sources such as fatty fish including salmon, mackerel, sardines, tuna, and herring.

Fat gets a bad reputation because it is the highest in calories and certain types of fat are not good for us, but if you can focus on the type of fat and amount of fat, it is instrumental to a healthy diet. However fats should be eaten sparingly as too much can lead to weight gain, heart disease, and some cancer.

Carbohydrates

All carbohydrates are eventually broken down into glucose, which is the main energy source for your body. In fact, specific organs, such as your brain, need glucose in order to function properly. Your body can make glucose out of necessity from proteins using gluconeogenesis. Beyond being your main energy source, there are carbohydrates that help synthesize specific amino acids (protein building blocks) and allow for consistent bowel movements. Fiber is a type of carbohydrate that cannot be broken down by your GI tract. Therefore, this nutrient does not give you energy, but it does help rid your body of waste and keeps your intestinal tract healthy. Carbohydrates are not all created equally. Some are considered simple carbohydrates and others are complex.

• Simple carbohydrates are easy for your body to breakdown for energy or glucose. They have 1-2 sugar molecules and are found in items that are usually sweet such as honey, table sugar, syrup, agave nectar, molasses, milk/yogurt, and fruit. Fruit does contain a natural sugar called fructose, however, fruit also has vitamins and minerals (these are your micronutrients: nutrients needed in small amounts), phytochemicals (not a needed nutrient, but can have positive effects on health), and fiber. Fiber is not digested and therefore, increases the amount of time needed to break down the food item.

• Complex carbohydrates take more time for your body to breakdown. They are long strands of sugar molecules strung together and typically have a savory taste. They are found in foods such as starches and grains: rice, pasta, bread, and starchy vegetables (potatoes, peas, corn). Other plant based foods such as non-starchy vegetables (beans, nuts, and seeds) contain carbohydrates, but in lower amounts. Complex carbs normally contain fiber unless they have been processed, where the grain has been stripped of its bran (outer coating), which gives us white bread, white pasta, white rice, etc. These types of carbs become easier for your body to digest. Even though they are not sweet they will release glucose quickly just like a sweet simple carbohydrate.

Proteins

Protein allows your body to grow, build and repair tissues, and protect lean body mass (your muscle mass). Protein is composed of amino acids. Amino acids are the building blocks of protein. There are 2 types of amino acids: non-essential and essential. Non-essential amino acids are not required to be consumed through the diet as your body can actually make these. Essential amino acids are required through your diet. Essential amino acids can either be used on their own or in some cases they are transformed into a non-essential amino acid. Protein rich foods include meat, poultry, fish, egg, milk, cheese, or other types of animal by-product foods. These protein sources contain all of your essential amino acids. This does not mean you have to eat animal foods to be healthy. You can get the proper amino acids from eating a variety of plant protein sources such as beans, lentils, nuts, seeds, and soy as well as lower amounts in grains, vegetables, and fruits.

Everyday you lose water through your breath, perspiration, urine, and bowel movements. For your body to function properly, you must replenish the water supply by consuming beverages and foods that contain water.

According to the National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake is: about 15.5 cups (3.7 liters) of fluids for men and about 11.5 cups (2.7 liters) of fluids for women per day.

These recommendations cover fluids from water, other beverages and food. About 20 percent of daily fluid intake usually comes from food and the remaining of total fluid per day come from beverages.

Empty calories are calories we get from solid fats/added sugars/alcohol in food items and drinks. These fats and sugars add few or no nutrients and are only added to foods to make them more appealing. According to the USDA, some foods and drinks that contain the most empty calories include: bacon, cakes, cheese, cookies, donuts, energy drinks, fruit drinks, hot dogs, ice cream, pastries, pizza, ribs, sausages, soda, and sports drinks.

While small amounts of empty calories are okay, eating too many can cause weight gain and is unhealthy, according to the USDA.

Liquid calories are calories found in things we drink. If you are trying to lose or manage your weight, it is important to remember that eating calories is a better choice than drinking them. Some types of drinks with liquid calories include: alcohol, coffee with sugar, fruit drinks, lemonade, milkshakes, punch, sports drinks, sugary sodas, and sweet tea.

Instead, try drinking more water, unsweetened tea, juices with no sugar added, and low-calorie drinks. Talk to your doctor for more information about liquid calories.

Caffeine is naturally found in many seeds, leaves, and more than 60 types of plants. Plants that naturally contain caffeine: coffee, cocoa beans (used in chocolate), kola nuts (used in many sodas), and tea leaves. Caffeine is often found in processed foods and medications: candies, chocolate, coffee, energy drinks, gum, many sodas, snacks, and teas. Some medications, including over-the-counter pain relievers, diet pills, and cold medicines also include caffeine.

Talk to your doctor for more information about what foods and drinks contain caffeine.

The best way to reduce added sugar in your diet is to avoid foods with excessive added sugar. Limiting and eliminating the following foods and drinks can be a great help: baked goods, candy and other sweets, processed foods, and sugary drinks (including soda and fruit punch). Sugary drinks are the number one offender with it comes to added sugar in foods in American diets.

Branched chain amino acids (BCAAs), including Leucine (Leu), Isoleucine (Ile), and Valine (Val), play critical roles in the regulation of energy homeostasis, nutrition metabolism, gut health, immunity and disease in humans and animals. Amino acids are the building blocks of protein. Essential amino acids are required through your diet. However, essential amino acids cannot be made by the body. As a result, they must come from food or beverage. The 9 essential amino acids are: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine.

This shows the percentage of certain nutrient in a food, based on a 2,000 calorie diet. The daily value gives you an idea of a food's nutrient contribution to your diet.

Dehydration occurs when body water loss exceeds intake. This generally occurs due to insufficient water consumption or increased water loss due to vomiting, diarrhea and/or excessive sweating. Symptoms include thirst, headaches, dry lips, lack of concentration, dizziness and/or blurred vision. Mild dehydration can occur before you notice any symptoms.

Diabetes mellitus is a metabolic disorder caused by the inability of the body to control the amount of sugar (glucose) in the blood. Type 1 diabetes results from the body's inability to produce insulin in the pancreas and Type 2 diabetes is due to the body cells developing resistance to insulin.

Electrolytes are minerals which are needed to keep the body's balance of fluids at a healthy level and to maintain normal functions, such as heart rhythm, muscle contraction, and nerve impulse transmission. Electrolytes include potassium, sodium, calcium, and magnesium.

Fiber plays a key role in preventing constipation, cancer and heart disease. Wholegrain breads, cereals, legumes, rice, pasta, fruit and vegetables are good sources of fiber. There are a number of different types of dietary fiber. The three major types are soluble fiber, insoluble fiber and resistant starch.

Soluble fiber

Soluble fiber is beneficial to help lower blood cholesterol levels and, people with diabetes to help control blood sugar. Soluble fiber is found in fruits, vegetables, dried peas, soybeans, lentils, oats, rice and barley.

Insoluble fiber

Because of its ‘bulking properties’, insoluble fiber helps keep us ‘regular’. Foods containing insoluble fiber include wholegrain and wholemeal wheat-based breads, cereals and pasta.

Resistant starch

Resistant starch is a type of starch found in plant foods that escapes digestion in the small intestine. Resistant starch may provide similar benefits to other types of fiber, such as helping to prevent constipation. Foods containing resistant starch include firm bananas, roasted chickpeas, boiled long grain white rice, baked beans, cooked and cooled potato, as well as cornflakes.

A food allergy is an abnormal reaction of the body's immune system to a protein in food. When the body comes in contact with the food protein, substances are released which cause inflammation (redness and swelling) and the symptoms of an allergic reaction. The symptoms of a true food allergy may include: an itchy rash, swelling or burning around the mouth and throat, vomiting, stomach cramps, hives, diarrhea, wheezing and eczema. Severe reactions may cause asthma and allergic shock (called anaphylaxis). The most common foods are linked with allergic reactions are: eggs, cows milk and peanuts, fish, wheat and soy.

A food intolerance is an adverse reaction (that does not cause an immune response) of the body to compounds found in a variety of foods. Common symptoms are irritation of the stomach or bowels, hives, mouth ulcers, nausea, nasal congestion and diarrhea. Food intolerance may also cause tiredness, weakness, headaches, irritability and muscle aches. Intolerance may occur to salicylates, amines and monosodium glutamate (MSG).

Glucose is a simple sugar derived from the breakdown of carbohydrates. Glucose is a major source of fuel for the body, particularly the brain.

Gluten is a protein found in wheat, rye, barley, and possibly oats (dependent on cross-contamination during processing). It is the gluten that gives dough its sticky cohesiveness which is important in manufacturing many products such as bread.

Insulin is a hormone produced in the pancreas in response to increased blood glucose levels. Insulin's primary role is to transport glucose from the bloodstream into the muscle and tissues.

Macronutrients are the key nutrients in the diet that provide us with energy. They are carbohydrate, protein and fat.

Metabolism refers to the chemical processes that occurs in our body that turn what we eat into energy. This energy can then be used for all activity including walking, talking, thinking and breathing.

Micronutrients is the general name given to compounds that are needed in minute quantities to sustain a healthy body, such as vitamins and minerals.

Minerals are important for the formation of bones, teeth, blood and connective tissues. They play important roles in chemical reactions, as they are a component of enzymes. Minerals also regulate water balance, muscle contractions and nerve transmissions. They are required in the body in small amounts and must be obtained from food.

Nutrients are substances obtained from food that we require for metabolism or physiological processes. Carbohydrates, fats, proteins, vitamins, minerals, fiber and water are all nutrients.

Protein allows your body to grow, build and repair tissues, and protect lean body mass (your muscle mass). Protein is composed of amino acids. Amino acids are the building blocks of protein. There are 2 types of amino acids: non-essential and essential. Non-essential amino acids are not required to be consumed through the diet as your body can actually make these. Essential amino acids are required through your diet. Essential amino acids can either be used on their own or in some cases they are transformed into a non-essential amino acid. Protein rich foods include meat, poultry, fish, egg, milk, cheese, or other types of animal by-product foods. These protein sources contain all of your essential amino acids.

Potassium and sodium work together in the body to regulate the balance between water and acidity in the blood. Potassium is also important for nerve function to the muscles which causes muscles (including the heart) to contract. If there is a deficiency in potassium, heart rhythm can be altered. Potassium can be found in fruits, vegetables, grain foods, meats and milk.

Recommended daily intake (RDI) is the average daily amount of all known nutrients that need to be consumed to maintain good health.

This section of a nutrition label helps you determine the number of calories and amount of each nutrient in a recommended serving of a food. USDA serving sizes are often smaller/larger than you might eat. Make sure to read labels carefully. Even small packages often contain more than one serving.

Sodium is an electrolyte that helps maintain acid-base balance of the blood, helps regulate blood pressure and water balance in cells and aids in muscle contraction and nerve impulse transmission. However, too much salt can lead to high blood pressure and stroke. Highly processed foods such as crisps and processed meats usually contain large amounts of sodium as it used to enhance the flavor and preservation of the food item.

Vegan is the word that describes an individual who avoids all animal-derived foods from their diet, including honey and gelatin.

There are two main types of vegetarian diets:

• 'Lacto-ovo' vegetarian - which includes dairy products and eggs along with all plant foods, such as grains, fruits and vegetables, pulses and legumes, nuts and seeds.

• 'Vegan' - which consists only of plant foods, avoiding all animal products including honey and gelatine.

With some planning, both of these diets can provide sufficient nutrients for good health.

Supplementation may be needed based on intake, lab values and physician diagnosis.

Vitamins are molecules that are needed in small amounts by the body for health and growth, and they must be obtained by the diet daily. The exceptions to this rule are vitamin D, which is made in the skin when exposed to sunlight and vitamin K, which can be synthesized by gut bacteria in small amounts. Vitamins play an essential role in releasing energy from food and in speeding up many chemical reactions that occur in the body every second. They also play important roles in the formation of body components, such as blood and bone as well as being antioxidants.

Water is one of the nutrients that our body requires for health and it makes up 50-70% of our body weight. All cells in the body require it and adequate water intake helps prevent dehydration. 6-8 cups of water are required each day, more than this may be required during hot weather or for active people.

Wholefoods are foods that are unprocessed, or minimally processed and as such contain high levels of nutrients. Good examples of wholefoods include fruit and vegetables, whole-grains, brown rice, nuts and seeds.

The word 'whole-grain' refers to a grain food where all parts of the grain are intact and retained. Examples include wholegrain wheat and wholegrain (brown) rice. If the grain has been cracked, crushed or flaked, then in order to be called 'wholegrain', it must retain nearly the same relative proportions of bran, germ and endosperm as the original grain.