Are You Hungry Or Just Thirsty? How To Decode Sneaky Hunger Cues

Ah, the age old question: Am I hungry, or just thirsty? We’re always told to listen to our bodies, but let’s be honest, sometimes it can be difficult to understand exactly what it’s trying to tell us—especially if you’re feeling weak, shaky, and downright irritable. It certainly doesn’t help that hunger and dehydration share some key markers, making it increasingly tricky to know exactly what you need to feel better.

If you’re feeling irrationally frustrated and easily irritated, there’s a good chance you’re hungry. Or, at the very least, according to functional medicine practitioner and NYT bestselling author Will Cole, D.C., burning through sugar quickly. “Many people I've worked with feel hangry and irritable if they go a few hours without eating,” he notes. “They often describe other frustrating side effects like fatigue, insatiable cravings, and brain fog."

If it’s been a while since you last ate, there's a good chance you'll experience a significant drop in energy, signaling it may be time to grab a snack. Especially if you got a good night's sleep, this dip in energy could be a telltale sign that your body is asking for food. "With the popularity of intermittent fasting and skipping meals, I find that people commonly choose to ignore their hunger cues but are having symptoms of hunger or low blood pressure," notes registered dietitian nutritionist Ginger Hultin, M.S., RDN, owner of ChampagneNutrition and author of the Meal Prep for Weight Loss 101 ebook. "If you're feeling light-headed, dizzy, low energy, or can't concentrate, you could actually need food!" 

It's also important to note that a high-carb meal may cause a blood sugar spike, followed by a subsequent crash, which could also be the culprit: "When these insulin levels peak after eating, this can lead to a crash in our blood sugars—leading, understandably, to that all-too-familiar post-lunch slump—a foggy brain and tired body," says Uma Naidoo, M.D., nutritional psychiatrist, professional chef, nutrition specialist, and author.

This one can be a little more difficult to differentiate, since a headache may be caused by both hunger and thirst. But while there is an overlap between hunger and thirst symptoms, Hultin notes, "I often find that when they need water, my clients experience a headache or feelings of low energy."

It's actually quite common to get a headache when your body needs some water. "When we are dehydrated, we have less volume inside our vessels, and flow of blood is more difficult, especially against gravity up into the head," board-certified neurologist Ilene Ruhoy, M.D., Ph.D., previously told mbg.

As for hunger, low blood sugar might mean your brain isn't getting the energy it needs from food, and can lead to headaches1. These type of headaches may also come with other side effects, like nausea or dizziness. It's also important to keep in mind that if you just ate a carbohydrate-rich meal (particularly a high-glycemic one), you may experience a blood sugar spike, which could also trigger headaches. So remember to opt for a balanced, nutritious meal with healthy fats, fiber, and protein to minimize this spike.