As the holiday season heats up, there’s no need to get stressed about what you can and can’t eat. Keep it simple, follow some basic guidelines, but don’t sweat the details.

“Healthy eating is far easier than you might think,” reports Dr. Frank Sacks, professor of cardiovascular disease prevention in the Nutrition Department at the Harvard School of Public Health in Boston, Mass. In Harvard’s booklet Healthy Eating, Sacks and colleagues outline the best ways to maintain your weight and fend off heart disease, hypertension, osteoporosis and some forms of cancer.

“Are there foods you should never eat?” they ask. “Not really. No matter how laden with saturated or trans fats, how devoid of nutrients or how high its glycemic load, there’s no food you can’t eat occasionally.” In the spirit of the season, if you crave candy cane ice cream, a pastry at the office party, or chips from the buffet, that’s OK every now and then, but make sure to choose healthier snacks at home.

“Healthy eating is not like many of the popular weight-loss plans that require you to eliminate certain foods entirely,” report the authors. While you don’t have to be perfect, there are some “baddies” you should eat only rarely. On the Harvard list of foods to keep to a minimum: red meat, high-fat dairy foods, sugary treats such as candy, drinks with added sugar, donuts and pastries such as cookies, pies, and high-fat muffins.

Balancing this out are foods that definitely get the green light: fruits and vegetables, nuts, fish, poultry, eggs and low-fat dairy products. As much as possible, go for whole grain breads and pastas instead of white, brown rice instead of white, and less-processed grains such as steel-cut oats. Oil can be healthy, if you use plant oils such as olive, sunflower, canola and other vegetable oils.

Here’s to happy, healthy eating.