When it comes to your health, should you feel guilty if you skip the gym, or eat cookies for dinner? Here are the "unhealthy" habits to avoid, and those that aren't so unhealthy after all. This comes from Self magazine. * What if you ate Oreos for dinner? The truth is: A once-a-week cookie dinner isn't so bad, if your diet is normally healthy and well-balanced, with lots of fruits, veggies, whole grains and lean protein. Registered dietician Janis Jibrin says don't eat the entire box, and add some low-fat milk for calcium. * Your weight's normal, but you don't always exercise 30 minutes a day, and you sometimes skip the gym entirely. It's not so bad. Cutting a workout short - or taking a few days off is no biggie, but normal weight doesn't always mean healthy. A Mayo Clinic study found that half of normal-weight people have a body fat percentage above 30% - which is the cutoff for good health. The benefits of exercise aren't just weight-related. Exercising 30 minutes on most days improves sleep, eases depression, and lowers your risk for diabetes and cancer. A few brisk 10 minute walks a day can work too. * You don't smoke, but you sometimes snag a cigarette from a friend. That's very bad because every puff raises your risk for arterial damage. A study at the University of Georgia found that just two cigarettes lower your body's ability to adapt to changes in blood pressure by 36%, raising your heart attack risk. * You tan, but only on vacation. Again, that's really bad. Any type of tanning could lead to skin cancer. In fact, dermatologist Dr. James Spenser says that short, intense bursts of sun exposure - like on a vacation - significantly raise your melanoma risk. Even one blistering sunburn raises your chance of developing skin cancer. So, always wear sunscreen of at least SPF 15, and use self-tanning lotions if you want a bronzed look.