Healthy diet can increase energy, athletic performance, weight loss, and chronic illness risk. Another reason to choose nutrient-dense foods: Food might affect your mood.

Food and mood are related, which is why "hangry" is in the lexicon. Understanding hormone regulation, blood sugar, and the brain-gut relationship will certainly keep it in the spotlight.

THE BLOOD SUGAR CONNECTION The major way your food choices turn into happiness, irritability or a whole range of emotional responses, is because of your blood sugar, also called blood glucose.

This is essentially fuel that moves through your bloodstream, and it’s the primary energy source for your body and brain, says Michelle Routhenstein, RD, owner of nutritional counseling practice Entirely Nourished.

SEROTONIN Research suggests that low intake of omega-3 fatty acids is linked to depressed mood, hostility and impulsive behavior, according to Routhenstein.

Researchers hypothesize that those reactions may be prompted by less release of serotonin, since high consumption of omega-3’s is associated with decreased depression and elevated mood.

FROM THE GUT TO THE BRAIN Harvard Medical School has noted that the brain has a direct effect on the stomach — for example, when you’re feeling scared, you might also become nauseous — but that the connection goes both ways

THE RIGHT FOODS TO EAT Focus on gut-happy favorites and you’re likely to get your blood sugar and inflammation on track as well. Eat more vegetables, fruits and other fiber-rich foods in order to encourage more microbial diversity.