You don’t have to wait for the next big medical breakthrough to start lowering your risk for cancer, the disease that kills more than half a million Americans each year. According to Washington University researchers, more than half of cancer cases could be prevented by applying knowledge we already have.

Amazing fact: One in three cancer deaths and 374,000 cases of cancer could be eliminated if Americans maintained a proper weight, followed a healthy diet and exercised daily, according to the American Institute for Cancer Research (AICR).

Six powerful, research-proven steps can lower your risk.

1. Mind your weight and waist. Keeping abdominal fat to a minimum helps rein in levels of hormones like insulin and estrogen that spur the growth of some cancers. A healthy weight and waist size could reduce your risk for fatal cancers by 20 percent, according to the American Cancer Society (ACS). Excess weight and belly fat are linked with cancers of the colon, esophagus, kidneys, pancreas, uterus and breast (in post-menopausal women), says the ACS.

Related: Men: The Secret to Losing That Belly

2. Munch on fiber-packed whole grains, produce and beans. Eating beans three times a week (how about chili on Monday, white bean soup on Wednesday and a bean burrito on Friday) could reduce your risk for precancerous colon growths called polyps by 33 percent, according to the National Center for Biotechnology Information. Also fill your plate with green vegetables, dried fruit and brown rice. They provide beneficial fiber plus vitamins, minerals and gene-protecting antioxidant compounds, say researchers from Loma Linda University. Non-starchy veggies and fruit may also protect against cancers of the mouth, esophagus and stomach thanks to their fiber and nutrients according to the AICR.

3. Try Meatless Monday. Slashing your red meat intake could lower your overall cancer risk by 40 percent. Stick to no more than 18 ounces a week and avoid processed meats like hot dogs, ham, bacon and salami, the AICR recommends. Preservatives called nitrates are carcinogenic, the group notes, as are compounds that form during smoking or high-heat cooking (like frying burgers or steaks).

Related: Going Vegan? 7 Things to Know Before You Start

4. Walk for 30 minutes today. Repeat tomorrow. The ACS says 30 minutes of exercise a day can lower your odds for cancers of the colon, breast, prostate, lungs and uterus.

5. Sip a mug of Joe. The AICR and ACS agree that plant chemicals in coffee activate antioxidants in your body that protect genes from mutations, helping to guard against cancers of the colon, prostate, mouth and uterus.

6. Show up for cancer screenings. Cancer checks can spot cancers early, when treatment works best — and even spot precancers in some cases. Ask your doctor about these tests:

Related: Women: Are You Due For a Screening? 

Colonoscopy: If you’re over age 50 (younger if you’re at high risk due to family history or other factors — check with your doc), the Department of Health and Human Services says it’s time to start colon-cancer screenings. The U.S. government estimates that 80 percent of all colon cancers and 60 percent of colon cancer deaths could be prevented with early detection that lets doctors find and remove polyps.

Mammograms: The ACS recommends women begin breast-cancer screening at age 40 (earlier if you’re at high risk — talk with your doctor). Despite a spate of recent studies questioning the value of mammograms before age 50, many breast cancer experts still recommend them for women at younger ages. In two recent studies, the breast checks reduced risk for deaths related to breast cancer by about 28 percent in women age 40 and older.

Prostate-specific antigen (PSA) tests: Men ages 50 to 74 who had PSA checks reduced their risk for fatal prostate cancer by 20 to 50 percent in one recent study from Sweden. But the scans are controversial in the United States. Some health organizations, including the United States Preventative Services Task Force, recommend against the test, and the ACS says it can produce unclear results, causing confusion and anxiety. The National Cancer Institute recommends discussing the pros and cons of prostate-cancer screening with your doctor. 

Skin checks: An exam by your doctor for suspicious moles could help spot melanoma (the most fatal skin cancer) early. The ACS recommends checking your own skin once a month in front of a full-length mirror to make sure moles, freckles or other marks have not changed color or shape. If they have, see a dermatologist.

Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.