If you're worried about holiday weight gain, fatty foods might not be the most important ones to avoid

If you're concerned about your diet - whether it's because of the threat of putting on "holiday weight" or simply because you'd like to eat healthier - fatty foods might not be the most important ones to avoid.

We know from decades of research that diets - particularly those that exclude certain foods - don't work. But if you want to start treating your body better this winter, studies suggest you should start curbing your intake of sweet, sugary foods rather than savory, fatty ones.

Decades of research have suggested that sugar is the real culprit when it comes to weight gain. When we eat too much sugar and don't balance it out with protein and fat, which our bodies breaks down more slowly, our blood sugar can spike and then plummet. These "crashes" can cause "hanger," or what's known as being angry and hungry at the same time.

This isn't surprising. All carbohydrates - bread, cereal, or potatoes - are ultimately broken down into glucose, which circulates in our blood and gives us energy. Sugars get broken down quickly and tend to raise blood glucose most dramatically.

And, according to the Centers for Disease Control and Prevention, most of the calories that Americans are getting from sugar are coming from processed foods like cereals, granola bars, breads, and cakes.

These basics are a good place to start for all meals, and for holiday ones too:

• Keep vegetables as the cornerstone of your meals. Or, in the words of journalist and food writer Michael Pollan: "Eat food. Not too much. Mostly plants."
• Snack on nuts. Since they're high in protein, nuts can help stabilize blood-sugar levels - which, if they plummet, can make healthy people feel "hangry" (hungry and angry) and can be especially dangerous for people with diabetes. Nuts are also a good source of fiber, a key nutrient that helps aid digestion and keeps us feeling full.
• Cut back on added sugar and refined carbs. Diets that are high in sugar and refined carbs (white rice, sweet snack foods, white bread) and low in whole grains (brown rice, whole wheat) have been linked with health problems, while diets high in whole grains and low in refined carbs tend to be linked with more positive outcomes.
• Incorporate oily fish like salmon into your diet. Salmon is rich in omega-3 fats, which help protect our cell membranes, the structure protecting the inner components from their outside environment. They are also the building blocks of the hormones that regulate blood clotting and inflammation.
• Eat avocados. While they're high in fat and calories - just half of one packs 120 calories, about the equivalent of a slice of bread - avocados are low in sugar and rich in fiber. So add a few slices to your next meal.