You’ve heard it before – maybe even said it: “It’s OK to devour this … bowl of guacamole/walnuts/olive oil for dipping bread … because it has healthy fats.”

Those fats are “unsaturated fats and omega-3 fatty acids, [which] promote components in the body that decrease inflammation,” says registered dietician Lona Sandon, assistant professor of clinical nutrition at University of Texas Southwestern Medical Center in Dallas. They also can benefit blood pressure and cholesterol, and may reduce the risk of type 2 diabetes, all health concerns associated with arthritis.

But it’s not healthy to gorge on them. All fats contain the same amount of calories – nine per gram, twice as many as those in carbohydrates and proteins. (Just two tablespoons of olive oil has 240 calories!) Excess calories leads to weight gain – and “being overweight promotes inflammation in the body,” Sandon says.

Eat these healthy, high-fat foods wisely.

Walnuts

Benefits: Rich in inflammation-fighting omega-3 fatty acids; can decrease LDL cholesterol and lower TNF-alpha and C-reactive protein, two markers of inflammation in the blood.

Moderate amount: 14 walnut halves (about ¼ cup) have 190 calories and 18 grams of fat.

Avocados

Benefits: Rich in omega-3 fatty acids, antioxidants and vitamin K, which helps blood clot properly and supports bone health

Moderate amount: One-sixth of an avocado – diced in an omelet or added to a salad – adds 5 grams of fat and 55 calories. Half an avocado is 15 grams of fat and 165 calories.

Keep Fat In Check

How much fat should you get in a day? According to the USDA’s 2010 Dietary Guidelines for Americans, total fat intake, both unsaturated fats and saturated fats (which are solid at room temperature, like butter and beef fat) should be 20 percent to 35 percent of your daily calories. Based on a 2,000-calorie-a-day diet, this ranges from roughly 44 to 78 grams of total fat per day – but the vast majority should be unsaturated.