Dietary fat

Dietary fats is a mixture of lipids – chiefly triglycerides. It is present in some quantity in all types of food -- animal products, vegetables, fruits and dairy products. With the rise in obesity related diseases such as heart disease and diabetes, fat has come under great scrutiny in the past few decades.

In the past four decades, the concept of healthy eating has become synonymous with avoiding dietary fat leading to the creation of reduced-fat food products to meet the rising demand from looks and health conscious individuals. So high was the demand, that an entire research industry has arisen to create palatable nonfat fat substitutes, which were marketed with less-fat-is-good-health message.

Why should I be aware of this?

• Fat is an essential nutrient.
• Fat is not all bad. There are some essential fats which are beneficial to us
• Most people eat far more fat than is needed for their health.
• The total amount of fat a person eats whether high or low, is not really linked with disease. What really matters is the type of fat a person eats.
• Fat free or low fat foods are not necessarily healthy or low in calories.

All about fat

Almost all foods contain some fat. Even quintessential fat-free foods like carrots and lettuce contain small amounts of this nutrient. Fat is an important part of cell membranes, helping govern what gets into cells and what comes out.

The U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS) recommend that fat make up no more than 35 percent of a person's daily calorie intake. Thus a person consuming 1,800 calories a day, should eat no more than 70 grams of fat daily.

• Fat is a source of energy. One gram of fat provides around 9 kcal.
• It aids the body in absorbing vitamins.
• Fat forms the basic building blocks for cell structure.
• Fats are an especially important source of calories and nutrients for infants and toddlers.
• Dietary fat also plays a major role in your cholesterol levels.
• Fat provides taste to foods and gives a feeling of fullness.
• Fat also is used by the body to maintain hair, nails and skin as well as to provide padding for your internal organs.

Fats can be classified as healthy fats and harmful fats.

Healthy fats

Healthy or good fats improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play a number of other beneficial roles. Unsaturated fats are predominantly found in foods from plants, such as vegetable oils, nuts, and seeds. They are liquids at room temperature.

There are two types of unsaturated fats:

1. Monounsaturated fats -- Monounsaturated fats are typically liquid at room temperature but start to turn solid when chilled. Monounsaturated fats are found in high concentrations in canola, peanut, and olive oils; avocados; nuts such as almonds, hazelnuts, and pecans; and seeds such as pumpkin and sesame seeds.
2. Polyunsaturated fats -- Polyunsaturated fats are typically liquid at room temperature and when chilled. They also include essential fats that the body needs but cannot produce itself – such as Omega-6 and Omega-3 fatty acids.

Harmful fats

Saturated and trans fats (trans-fatty acids) are less healthy kinds of fats. They can increase your risk of heart disease by increasing your total and LDL ("bad") cholesterol.

1. Saturated fats -- Saturated fats are typically solid at room temperature. Saturated fats come mainly from animal sources, including meat and dairy products. Examples are fatty beef, lamb, pork, poultry with skin, beef fat (tallow), lard and cream, butter cheese and other dairy products made from whole or reduced-fat (2 percent) milk. Coconut oil, palm oil and other tropical oils also have saturated fats.
2. Trans fat -- Trans fat is a result of hydrogenation of vegetable oil. Manufacturers go for the process of hydrogenation, as it increases the shelf life and flavor stability of foods containing these fats. Trans fat can be found in vegetable shortenings, some margarines, crackers, cookies, snack foods, and other foods made with or fried in partially hydrogenated oils.

What can I do?

The American Heart Association's Nutrition Committee strongly advises these fat guidelines for healthy Americans over age 2:

• Limit total fat intake to less than 25–35% of your total calories each day.
• Limit saturated fat intake to less than 7% of total daily calories.
• Limit trans fat intake to less than 1% of total daily calories.
• Add slices of avocado, rather than cheese, to your sandwich.
• Use olive oil for cooking food and seasoning salads.
• Replace red meat with fish such as salmon and mackerel, which contain monounsaturated and omega-3 fats.

Unlearn

• Eating low fat or no fat food will not necessarily make a person slimmer. To get the low fat or fat free tag on their lables, many pre-packaged foods remove the dietary fat and add sugar, salt or preservatives to make up for the loss of taste.

CopperBytes

• Dietary fat has over twice as many calories as the same weight of starch or protein.
• Margarine and butter have the same amount of calories and fat. However, butter is rich in both saturated fat and cholesterol. Most margarine is made from vegetable fat and provides no dietary cholesterol.
• The more liquid the margarine, the less hydrogenated it is and the less trans fat it contains.
• The total amount of fat suggested per day is about 70g for women and 90g for men.
• Fat also is used by the body to maintain hair, nails and skin as well as to provide padding for your internal organs.

References

• Getting the balance right
• Dietary fats: Know which types to choose
• Know Your Fats: American Heart Association
• Dietary Fat(Centers for Disease Control and Prevention)
• The Nutrition Source: Fats and Cholesterol Harvard School of Public Health
• Monounsaturated Fats: American Heart Association
• Polyunsaturated Fats: American Heart Association