Many people spend the majority of the morning looking forward to lunch, so as lunchtime approaches and you develop a headache and nausea so severe that eating is the last thing you want to do, it can sour your whole afternoon. The old wives' tale is right -- eat something, and it will settle your stomach. Unlike headaches and nausea caused by viruses or other pathogens, your own body is responsible for the way you're feeling. The food you're turning away from is the very thing that will make you feel better.
Glucose
Low blood sugar is typically the root cause of pre-meal headaches. It's not that you're about to eat, it's that you haven't eaten in a while, and your body's energy sources are running low. Glucose is the fuel your body burns to get you through the day. It's in everything you eat, and meals are nothing more than refueling pit stops. Think of your car -- it runs well on a full tank of gas, but as the gas runs out, the engine begins to sputter and eventually cruises to a stop. Without gas, the car can't move -- the same is true for your body.
Factors
If you skip breakfast, you may feel this "hunger headache" shortly before lunch. Your body hasn't been fed since the previous day, so fuel is in short supply. You're tense from working all morning, which is enough to trigger a headache in itself, and your blood vessels are dilating in an effort to slow things down to conserve fuel -- it is the dilation of the blood vessels that triggers the pain of a headache. If you started the day with coffee, the effect is even more pronounced as the caffeine wears off and blood vessels dilate even further as adrenaline levels die down.
Nausea
The attendant nausea is caused by a couple of factors. It is a symptom of low blood sugar, and the type of headaches caused by a combination of hunger and stress can cause nausea as well. If caffeine made an appearance that morning, the nausea can also be caused by the beginnings of withdrawal, and some people experience stomach irritation and nausea after drinking coffee in particular. Basically, your body is telling you that you need to eat, and shame on you for waiting so long.
Eat More
Eating small, frequent, balanced meals can eliminate hunger headaches altogether by keeping your blood sugar at constant steady levels. Eat carbohydrates and a small amount of protein at every meal, and avoid refined carbs like white flour and sugar. Refined carbs make your blood sugar spike rapidly, but they diminish quickly and your blood sugar drops. Eat a small mid-morning snack -- a 2006 study in the "Journal of School Nursing" found that students fed a 9a.m. snack experienced a dramatic drop in hunger-induced headaches and nausea, and were better able to focus. Headaches and nausea can also be caused by a number of medical conditions, so consult your doctor if symptoms continue.
