We’ve all been there. A co-worker brings in cupcakes or potato chips for the office, and you succumb to the siren call of free food -- only to fight off the urge to nap afterward. Nutrition and eating habits have a direct hit on energy level, mental sharpness and motivation, says Elizabeth DeRobertis, a registered dietician and nutritionist at Scarsdale Medical Group, who recommends strategic snacking.

“The idea of strategic snacking is to identify the right snacks that fill you up and hold you over but also don't become a trigger -- leaving you craving more snacks," she says.

A healthy snack should be about 100 calories to 150 calories and nutrient-dense, advises DeRobertis. “It should also be pre-portioned, so that you don't need to worry about counting or measuring when you are at work and have other distractions.” Space two snacks two hours apart following lunch. Strategic snacking can keep your appetite in check, maintain your energy level and keep your body balanced -- plus stop you from overeating.

Here are ten snacks that are nutrient-dense and will help keep you satisfied.