Dietary fat is very easily converted to body fat (at any age), so controlling your fat intake is crucial to control the weight gain associated with ageing. Each gram of fat you eat contains nine calories, regardless of what type of fat it is. A tablespoon of vegetable oil contains 14 grams of fat and 125 calories. That can add up! You must avoid any foods that are higher than 30 percent fat content. Items high in fat and saturated fat are lard, animal shortening, oils, butterfat, whole-milk solids, shortening and margarine. You should focus on eating fresh, wholesome foods and avoid processed foods as much as possible.
There are fats that are good for us however. Fatty acids are necessary for good health, and some fat-soluble vitamins require fat for absorption into the system.Fat also helps to keep us insulated and warm. Elderly persons who have lost weight due to reduced appetite need to consume a moderate amount of dietary fat to maintain a healthy weight. Unsaturated fats, especially the monounsaturated ones, are considered "the healthy fats." These fats can be found in oils such as olive and sunflower, seeds, nuts, avocados and even in some margarine products.
Polyunsaturated are fats that can have a beneficial effect on your health when consumed in moderation and when used to replace saturated fats or trans fats. Polyunsaturated fats can help reduce the cholesterol levels in your blood and lower your risk of heart disease. They also include essential fats that your body needs but can’t produce itself – such as omega-6 and omega-3. You must get essential fats through food. Omega-6 and omega-3 play a crucial role in brain function and in the normal growth and development of your body. Most foods contain a combination of fats. Foods high in polyunsaturated fat include a number of vegetable oils, including soybean oil, corn oil and safflower oil, as well as fatty fish such as salmon, mackerel, herring and trout. Other sources include some nuts and seeds such as walnuts and sunflower seeds. 
Saturated, or "unhealthy fats," are found in red meat, dairy products (cheese, butter, ice cream) and lard. They are generally solid at room temperature. These fats contribute to higher blood cholesterol levels, thereby increasing increasing risk of heart disease. Certain vegetable oils such as palm and coconut contain large amounts of saturated fat, so use in moderation as much as possible. As for red meat, try ground white turkey breast instead. With the right seasonings you can't tell the difference! 
Unlike other dietary fats, trans fats are not essential, and they do not promote good health. The consumption of trans fats increases one's risk of coronary heart disease by raising levels of "bad" LDL cholesterol and lowering levels of "good" HDL cholesterol. Trans fats from partially hydrogenated oils are more harmful than naturally occurring oils. Trans fats can be found in many foods – but especially in fried foods like French fries and doughnuts, and baked goods including pastries, pie crusts, biscuits, pizza dough, cookies, crackers, and stick margarines and shortenings. You can determine the amount of trans fats in a particular packaged food by looking at the Nutrition Facts label. You can also spot trans fats by reading ingredient lists and looking for the ingredients referred to as “partially hydrogenated oils.” Several large studies indicate a link between consumption of high amounts of trans fat and coronary heart disease, and possibly some other diseases. The United States Food and Drug Administration (FDA), the National Heart, Lung and Blood Institute and the American Heart Association (AHA) all recommend that people limit their intake of trans-fat.
Following is a table with the most commonly used fats and oils and their corresponding saturated, monounsaturated and polyunsaturated percentages:
| Type of Oil or Fat | Saturated | Monounsaturated | Polyunsaturated |
| Butter | 66% | 30% | 4% |
| Clarified butter | 65% | 32% | 3% |
| Canola oil | 6% | 62% | 32% |
| Coconut oil | 92% | 6% | 2% |
| Corn oil | 13% | 25% | 62% |
| Cottonseed oil | 24% | 26% | 50% |
| Grape seed oil | 12% | 17% | 71% |
| Lard | 41% | 47% | 2% |
| Margarine, hard | 80% | 14% | 6% |
| Margarine, soft | 20% | 47% | 33% |
| Diacylglycerol (DAG) oil | 3.5% | 37.95% | 59% |
| Olive Oil(Extra Virgin) | 14% | 73% | 11% |
| Olive oil (Virgin) | 14% | 73% | 11% |
| Olive Oil (Refined) | 14% | 73% | 11% |
| Olive Oil (Extra Light) | 14% | 73% | 11% |
| Palm oil | 52% | 38% | 10% |
| Peanut oil | 18% | 49% | 33% |
| Rice bran oil | 20% | 47% | 33% |
| Safflower oil | 10% | 13% | 77% |
| Sesame oil (Unrefined) | 14% | 43% | 43% |
| Sesame oil (Semi-refined) | 14% | 43% | 43% |
| Soybean oil | 15% | 24% | 61% |
| Sunflower oil (Linoleic) | 11% | 20% | 69% |
| Sunflower oil (High Oleic) | 9% | 82% | 9% |
Hopefully this helped you to get a basic understanding of the types of fats and which ones you should be sure to add to your diet. A word to the wise: too much of any fat, even good fat, will make you fat. Being cognizant of how much fat you are consuming will go a long way to help you lose weight and keep it off.
