How Fast Does a Diet Affect Cholesterol Levels?

Because so many variables affect your cholesterol, it's difficult to pinpoint an actual amount of time it takes to lower it. The type of diet you follow, any weight loss or exercise you do, smoking cessation and medications will all affect how quickly you lower your levels. HDL, LDL and total cholesterol are also affected differently by different diets and activities.

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Fasting Versus Not Fasting

LDL, the "bad" cholesterol, and triglycerides are affected by the food you've eaten recently. Total cholesterol and HDL, the "good" cholesterol, take longer to change. For this reason, your health care provider may ask you to fast before your cholesterol screening. The American Heart Association recommends you get your cholesterol checked every four to six years. If you have other cardiovascular risk factors, your health care provider may want you to get checked more often.

Low-Fat Diet

An article published in 2012 in the "Journal of Internal Medicine" reviewed several diets and their effect on different types of cholesterol. Low-fat diets were found to have very little effect on cholesterol levels. However, if you follow a low-fat diet and lose weight, you will most likely reduce your cholesterol level since weight loss lowers your LDL, total cholesterol and triglycerides and raises your HDL cholesterol. Losing just 5 to 10 percent of your weight reduces your risk of heart disease. How quickly it affects your cholesterol level depends on how fast you lose weight.

Substituting Carbs for Saturated Fats

The "Journal of Internal Medicine" review found that people who cut saturated fats from their diet and substituted them with carbohydrates did not improve their cholesterol level. One study in the review compared participants following an olive oil-rich diet to those following a diet high in complex carbohydrates. Both groups reduced their total cholesterol within 13 days. However, the carb group had lower HDL and higher triglyceride levels, both of which could increase your risk for cardiovascular disease.

Mediterranean-Type Diet

According to the "Journal of Internal Medicine" article, if you substitute the saturated fats in your diet with mono- and polyunsaturated fats, you should reduce your cholesterol without reducing your HDL or increasing your triglycerides. A Mediterranean-type diet -- which includes olive oil, plenty of fish and seafood instead of red meat, plant-based meals, grains, fruits, vegetables, nuts and legumes -- can improve your cholesterol. Other unsaturated fats include vegetable oils, avocado, olives and nuts. The saturated fats that increase your LDL the most include butter and dairy products followed by beef fat. Depending on how strict you are with your diet, you might see improvement in your cholesterol level anywhere from a few weeks to several months.

Warning About Trans-fats

Eliminating trans fats from your diet will also help improve your cholesterol level. According to the "Journal of Internal Medicine" review, a diet that includes 10 percent of calories from trans fats raises LDL cholesterol and lowers HDL cholesterol at the same rate as saturated fats. Trans fats are found mostly in processed foods. If a food contains partially hydrogenated oils in the list of ingredients, it contains trans fats, and you should choose a healthier option.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.
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