Thousands of folks usher in each New Year with a resolve to adopt a healthier diet and exercise plan. But new research suggests one type of diet could actually wreak havoc on your memory!

According to a Reuter’s report, researchers at Tufts University in Massachusetts said low-carb diets may play a role in clouding your short-term memory. But they found these same diet strategies could actually improve your ability to focus and pay attention.

This is because cutting down on carbs can cause you to have low blood sugar levels, or hypoglycemia. This is known to worsen brain function. Low-carbohydrate diets can force your body into ketosis—which causes your body to use fat as fuel.

The fact that doctors often use low-carb diets to trigger ketosis for controlling seizures “suggests that they can profoundly influence brain functioning,” said lead researcher Holly A. Taylor, Ph.D. “Low carbohydrate is okay; no carbohydrate is not,” she said.

Taylor said low-carb diets initially begin as NO-carb diets—and this is when they have the greatest potential to impair brain function. This is because glucose is the primary fuel for your brain.

Your body breaks carbohydrates down into smaller components—such as glucose—that travel through your bloodstream to nourish your brain and other body parts. When a low-carb diet begins to deplete your carbohydrate stores, your brain will begin to starve.

During the study, 19 women chose one of two diets: 1) a low-calorie, balanced diet recommended by the American Dietetic Association (ADA), or 2) a diet in which they cut out carbohydrates completely for a week and then gradually began to eat them again.

Study participants completed several tests of mood and brain function 72 hours before they began the diets. They repeated the tests at 48 hours, one week, two weeks and three weeks after starting the diet.

The results? The nine women who chose the low-carb diet showed the worst performance on memory tests during the first week of the diet, when no carbohydrates were allowed. What’s more, when they started eating carbs again, the memory differences between the two groups disappeared!

After the first week, the group of low-carb dieters performed better on a test of sustained attention than the low-calorie dieters. They also reported feeling less confused.

The current findings are reported in the journal Appetite.