Lipids

Lipids (fats) are the most concentrated source of energy at 9 calories per gram. This may be the reason that there is such a focus on fat intake for weight loss. However lipids are also have a role in many other essential body functions that maintain health.

Functions of Lipids

Lipids perform essential functions in the body, including energy storage, insulation, cell structure, hormone production, vitamin absorption, organ protection, and regulation of various physiological processes. 

• Energy storage: Lipids are converted into fatty acids for long term energy storage, which can be used for fuel when needed. 
• Insulation: Subcutaneous fat (fat under the skin) insulates the body, protecting it from cold temperatures or impact. 
• Cell Membrane Structure: Phospholipids, a type of fat, are essential components of cell membranes. They help maintain cell structure and regulate what enters and exits the cell. 
• Hormone Production: Fats are precursors to certain hormones, such as estrogen, testosterone, and progesterone. 
• Vitamin Absorption: Fats help absorb fat-soluble vitamins (A, D, E, and K) from the intestines. 
• Protection of Organs: Visceral fat (fat around organs) cushions and protects vital organs, such as the heart and kidneys. 
• Regulation of Blood Clotting: Certain fatty acids, such as omega-3 fatty acids, help regulate blood clotting. 
• Signal Transduction: Fats play a role in cell signaling, influencing processes such as inflammation and metabolism. 
• Flavor and Texture: Fats contribute to the flavor and texture of food.

Depending on the fatty acid structure a lipid may be monounsaturated, polyunsaturated, or saturated. Monounsaturated and polyunsaturated fats are considered healthy fats, while saturated fats are generally less healthy and should be consumed in moderation. Monounsaturated fats have one double bond in their chemical structure, while polyunsaturated fats have more than one, and both can help reduce “bad” LDL cholesterol. Saturated fats have no double bonds and, when consumed in high amounts, can raise cholesterol and increase the risk of heart disease. 

Monounsaturated Fats

This type of fat is found in plant oils. Common sources are nuts (almonds, cashews, pecans, peanuts, and walnuts) and nut products, avocados, extra virgin olive oil, sesame oil, high oleic safflower oil, sunflower oil, and canola oil.

Polyunsaturated Fats

This type of fat is found mainly in plant-based foods, oils, and fish. Common sources are nuts (walnuts, hazelnuts, pecans, almonds, and peanuts), soybean oil, corn oil, safflower oil, flaxseed oil, canola oil, and fish (trout, herring, and salmon).

Linoleic acid (omega 6) and alpha-linoleic acid (omega 3) are examples of polyunsaturated fats and are essential components of a healthy diet. These healthy fats have an interactive roll in cell metabolism as well as overall vascular health which reduces risk of certain types of heart disease.

Saturated Fats

This fat is found in animal products, dairy products, palm and coconut oils, and cocoa butter. Limit these products to less than 10 percent of your overall dietary fat consumption. Saturated fat, which is found in meat, dairy products, and some plant oils, is associated with increased bloodstream cholesterol.  High cholesterol levels indicate that a person is at a major risk for disease, such as heart attack.  Avoid saturated fat, or at least consume in moderation.

Triglycerides

Cholesterol

Cholesterol is a form of lipid the body uses as a building block to produce hormones, vitamin D, and digestive juices that help break down fats in the diet. The body needs some cholesterol to function, but when levels get too high, fatty deposits can accumulate in blood vessels, which causes them to narrow. This narrowing of the blood passageways by these lipids can lead to heart attacks, coronary artery disease, strokes, or other vascular diseases.

• HDL (high-density lipoprotein) – HDL cholesterol can be thought of as the “good” cholesterol because a healthy level may help protect against heart attack and stroke. HDL carries LDL (bad) cholesterol away from the arteries and back to the liver, where the LDL is broken down and passed from the body.
• LDL (low-density lipoprotein) – LDL cholesterol is considered the “bad” cholesterol because it contributes to fatty buildups in arteries. This narrows the arteries and increases the risk for heart attack and stroke.

Trans-Fats

When unsaturated fats go through a process of hydrogenation some fatty acids are changed to trans-fats. This hydrogenation process makes liquid fats (such as oils) solid at room temperature and resistant to spoilage. Many food manufacturers used hydrogenated oils in processed foods to give these foods a longer shelf-life. However, trans-fats have a negative impact on health by raising levels of bad cholesterol (LDL) and lowering good cholesterol (HDL). Trans-fats are associated with increased risk of heart disease, stroke and type-2 diabetes.

Recommended Intake

So if you aim to take in 2,000 calories a day, between 600-700 calories should be from healthy (mono and polyunsaturated) fats.  Fats give you about 9 calories a gram, so that’s between 66-70 grams of fats a day.