#1: Sitting all day.
Even if you exercise regularly, habitually sitting for prolonged periods, whether at a desk or in a car, is being increasingly linked to a variety of health problems. According to Alberta Health Services-Cancer Care in Canada, inactivity is linked to nearly 160,000 cases of breast, colon, prostate, and lung cancer every year, about two-thirds as many cancer cases caused by smoking.
Make it right: Make it a habit to take breaks on-the-move at work, and even make (or buy) a standing workstation so you're less apt to sit all day. At home, resist the temptation to veg out in front of the TV. Go for a short walk around the block to relax, spend a few minutes cleaning, or schedule a gym date with your significant other.
#2: Eating too much meat and cheese.
Animal proteins are rich in IGF-1, a growth hormone that can promote the growth of cancer cells. And a study from the University of Southern California published in the journal Cell Metabolism recently found that people on high-animal-protein diets during middle age were four times more likely to die of cancer than people on low-protein diets—a mortality risk factor comparable to smoking.
Make it right: Replace some of your animal proteins with vegetarian protein sources. The same study found that diets high in plant-based proteins like beans, which have protein levels equivalent to some meats, didn't trigger the same increase in cancer rates. In general, middle-aged adults should be eating 0.8 grams of protein for every 2 pounds of body weight daily. Interestingly, the study found that once you pass the age of 65, eating lots of animal protein isn't as harmful because your body's production of IGF-1 begins to slow down.
#3: Cooking with natural gas.
If you're one of the 34 percent of Americans whose home is equipped with a gas stove, you're getting an added dose of carbon monoxide, nitrogen dioxide, and formaldehyde every time you cook a meal. Those same three contaminants are common in secondhand cigarette smoke, and a December 2013 study in Environmental Health Perspectives found that all three contaminants in homes with gas stoves regularly exceeded public health guidelines.
Make it right: Use your vent hood when you use your gas oven or cooktop. Ventilating a gas range can reduce pollutant levels by 60 to 90 percent, even if the fan seems wimpy. Also, cook on your back burners: Most vent hoods aren't properly centered over a cooktop; using the back burners will help your vent hood capture the most pollution.
More: 11 Hidden Sources of Indoor Air Pollution
#4: Cooking with the wrong oil.
Even if you rely on an electric stove at your house, you aren't immune to cooking's polluting effects. Studies on restaurant and residential kitchens have shown that high-heat cooking with shortening and soybean oil (usually just called "vegetable oil" in the U.S.) releases particulate matter, aldehydes, and polycyclic aromatic hydrocarbons, all compounds found in cigarette smoke and linked to airway inflammation.
Read More: A World Without Cancer
Make it right: Pick the type of cooking oil best suited your use. For instance, olive oil isn't good for frying or high-heat cooking but is fine for cooking at low temperatures or in salad dressings. Avocado oil, on the other hand, is great for high-heat cooking. Look for the "smoke point" on oils that you buy to make sure the oil matches your needs. And don't forget to run the ventilation hood!
#5: Tanning indoors.
A recent study in the Journal of the American Medical Association estimated that indoor tanning causes roughly 420,000 cases of skin cancer in the U.S. every year. Smoking, by comparison, causes 226,000 cases of lung cancer.
Make it right: Learning to love pale skin is step number one. But if you really want a natural glow, eat more carrots and tomatoes, suggests a study published in the journal Evolution and Human Behavior. Both foods are rich in carotenoids, which will boost your skin tone, and you won't have to worry about exposure to sketchy ingredients in sunless tanning sprays and lotions.
#6: Not getting enough sleep.
This will make you really cranky: Chronic sleep deprivation triggers high blood pressure, heart attacks, strokes, obesity, and a host of other health problems. One study even found that not getting at least six or seven hours of sleep led to mortality rates on par with those seen in cigarette smokers. Even getting poor-quality or fragmented sleep—when you don't necessarily fully wake up, but the cycle from light to deep sleep gets interrupted—can speed the growth of tumors.
Make it right: Don't assume that being tired is normal. If you feel like you aren't getting enough sleep regularly, talk to a health professional to see if you might be suffering from a condition such as sleep apnea that is interfering with your sleep.
More: 5 Natural Sleep Aids