Where HDL is concerned, “you can’t be too thin,” Castelli says. One report found about a 1 percent rise in HDL for every pound of fat lost. This doesn’t mean you have to turn yourself into a toothpick, but that you should work on getting rid of excess flab as you add muscle. (Use a body-fat monitor rather than a scale to chart your progress.) Fortunately, fat loss is likely to go hand in hand with the exercise and dietary modifications that also raise HDL levels.

Cholesterol is carried through the bloodstream attached to two different compounds called lipoproteins: low-density lipoproteins (LDL) and high-density lipoproteins (HDL). LDL is commonly known as the “bad” cholesterol because it transports cholesterol from the liver throughout the body, and potentially allows it to be deposited in artery walls. HDL, known as the “good cholesterol,” picks up cholesterol from the blood and delivers it to cells that use it, or takes it back to the liver to be recycled or eliminated from the body.
An easy way to make the switch from trans fats is by replacing them with unsaturated fats, which don’t increase your LDL cholesterol, according to WebMD. Unsaturated fats are found in olive oil, canola oil, vegetable and sunflower oils, as well as fish, nuts, seeds and avocados. Just as unsaturated fats are healthy choices, unsaturated fats are not. Be sure to limit your intake of unsaturated fats, which are found in fatty meats, cold cuts, whole milk, whole-milk cheeses and many store-bought baked goods and snacks. Instead, enjoy lean cuts of meat, skim milk, low-fat cheeses and yogurt, and wholesome snacks to trim down your cholesterol levels. 
What is the difference between HDL and LDL cholesterol? The body needs cholesterol, but too much bad cholesterol can be harmful and is a major risk factor for heart disease and stroke. In this article, learn about the difference between HDL and LDL — “good” and “bad” — cholesterol, as well as how they are measured. What steps can you take to lower LDL and increase HDL? Read now
More long-term studies are needed in order to determine whether or not it is the actual loss of weight or the diet and exercise that go along with it that causes the reduction in LDL levels. It is also possible that LDL cholesterol can eventually return to original levels, even when weight loss is maintained. Nonetheless, the prospect makes weight maintenance and good nutrition worthy goals to have.
Catapano AL, et al. 2016 ESC/EAS guidelines for the management of dyslipidaemias: The task for the management of dyslipidaemias of the European Society of Cardiology (ESC) and European Atherosclerosis Society (EAS) developed with the special contribution of the European Association for Cardiovascular Prevention & Rehabilitaiton (EACPR). Atherosclerosis. 2016;253:281.

Coronary heart disease: What you need to know The coronary arteries supply oxygen and blood to the heart. They can narrow, often because cholesterol accumulates on the arteries’ walls. This results in coronary heart disease, the most common type of heart disease in the U.S. Here, learn about risk factors, early warning signs, means of prevention, and treatments. Read now
Heart-healthy eating. A heart-healthy eating plan limits the amount of saturated and trans fats that you eat. It recommends that you eat and drink only enough calories to stay at a healthy weight and avoid weight gain. It encourages you to choose a variety of nutritious foods, including fruits, vegetables, whole grains, and lean meats. Examples of eating plans that can lower your cholesterol include the Therapeutic Lifestyle Changes diet and the DASH eating plan.
Saturated fats. Typical sources of saturated fat include animal products, such as red meat, whole-fat dairy products, and eggs, and also a few vegetable oils, such as palm oil, coconut oil, and cocoa butter. Saturated fat can increase your levels of "bad" LDL cholesterol. But it has some benefits, too — it lowers triglycerides and nudges up levels of "good" HDL cholesterol.
However, although low levels of HDL predict increased cardiovascular risk, particularly in healthy individuals with no history of cardiovascular events, the relationship between HDL and CHD risk is complex, with HDL-C and cardiovascular disease having a nonlinear relationship. For example, research found that HDL levels above approximately 60 mg/dL showed no further improvement in prognosis, and the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk and IDEAL (Incremental Decrease in End Points through Aggressive Lipid Lowering) studies showed that very high levels of HDL may actually be associated with an increased risk of atherosclerotic disease. [5, 6, 2]
If you’re getting worked up over high cholesterol, then start working out. Daily exercise can help raise your HDL cholesterol levels and reduce your LDL cholesterol, while protecting you from many health conditions. Begin by choosing an activity that sounds like fun to avoid “workout burn-out.” Consider jogging, brisk walking, cycling, tennis, swimming or hitting the gym. Find an exercise partner to make the activity more enjoyable and help you stay on track. And while exercise can lower your cholesterol, it can also reduce your stress and anxiety. So working up a sweat can also save you from sweating the small stuff.

Of course, this was an N=1 experiment, meaning there’s only one subject in his experiment. It’s possible that Feldman is unusual. He thought the same thing, so he shared his data and sent an open invitation to people to try the protocol for themselves. As of now, more than 50 people have followed Feldman’s experiment. Virtually all of them reported the same results (it’s worth noting that they’ve all been on a high-fat, low-carb diet).
As a result of all this, doctors don’t just want you to lower your total cholesterol count; they want you to change the ratio as well, so you have more HDL and less LDL. “When we looked at the data, we found that the higher your HDL went, the lower your risk of heart attack,” says cardiologist William Castelli, M.D., former director of the Framingham Heart Study in Massachusetts. An HDL level of 75 or more seems to convey extra longevity for many people, while a count of 100 or more is so beneficial that it was dubbed the “Methuselah syndrome” by one researcher. HDL less than 35 or so, meanwhile, can carry significant risk of heart disease. Genetics plays a large role in HDL. A few guys have naturally low levels and need to keep their LDL low as well to make up for it. (As Castelli puts it, you don’t need a substance that removes cholesterol from your blood if you don’t have much to begin with.) But there’s plenty that everyone else can do to pump up their HDL. Never one to shirk from a task that doesn’t involve housecleaning, I managed to find two handfuls of ways to turn my “good” numbers into great numbers.

If you smoke, it’s time to pack it in. According to the American Heart Association, smoking reduces your HDL cholesterol levels, while increasing your risk of heart disease, high blood pressure and diabetes. If you’re a smoker, you need to quit. Once you stop smoking, you can significantly improve your HDL cholesterol level very quickly and start protecting your heart. And if you’re a non-smoker, you need to avoid exposure to second-hand smoke to prevent your health from going up in smoke.
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