By Alok Jha, The Guardian Wednesday, October 17, 2012 7:47 EDT
Brain scans show people who miss meal respond more positively to unhealthy foods than those who have eaten
We are all told that breakfast is the most important meal of the day - and now neuroscientists are starting to understand why. Skipping the first meal of the day not only means you eat more at lunch, research has found, but also means your brain is primed to seek out unhealthier, higher-calorie foods.
Dieters who skip meals often end up gaining weight over the long term, but why this happens is not well understood. Tony Goldstone, of the MRC Clinical Science Centre at Imperial College London, scanned the brains of people who skipped meals and found mechanisms at work that could help explain the conundrum.
Prolonged fasting of any kind seemed to prime certain brain regions to gravitate towards higher-calorie foods when the person did eventually find a meal. "That makes evolutionary sense if you're in a negative energy-balance situation," he said. "You're not going to waste your time going for lettuce." He will present the results of his study on Wednesday at the annual meeting of the Society for Neuroscience in New Orleans.
In the experiment, Goldstone scanned the brains of 21 men and women, all around the age of 25, on two separate days while they were shown pictures of food and asked to rate how appealing they found everything from chocolate and pizzas to vegetables and fish. On one of the days, the volunteers skipped breakfast before their scans; on the other, they were given a 750-calorie breakfast of cereals, bread and jam an hour beforehand. After the scans on both days, the volunteers were given lunch, where they could eat as much as they liked.
"Not surprisingly, when they are fasted they are hungry and they rate the high-calorie foods as more appealing than when they are fed," said Goldstone. "For low-calorie foods, the effect is not as marked. When they come out of the scanner, they are given lunch and they eat more when they haven't had breakfast."
When the volunteers had skipped breakfast, they ate around 20% more at lunch, compared with days when they had eaten a normal breakfast. Their brain scans also showed that activity in the orbitofrontal cortex, which is just above the eyes, was especially responsive to high-calorie foods. "We believe that bit encodes the value of rewards - how rewarding, how pleasant, how tasty something is. Not just food but other rewards seem to be signaled there in the brain," said Goldstone.
The more you like the food you're eating, the more active the orbitofrontal cortex becomes, and when people are asked to suppress their desire for tasty foods, its activity drops.
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What do you eat for breakfast?
I don't skip meals (blood sugar issues), an especially not breakfast. I also don't really distinguish between meals foodwise. That is, I can eat tuna as easily for breakfast as for dinner 
Like a day or so ago, for "breakfast" I had half a can of tuna, sauerkraut (have with most meals to help digestion), and two of my little "famous" mini "pizzas." Ha. I put 2 Kavli crackers on a pie plate (so it will fit in my convection oven--no microwave for me), spread a thick layer of my favorite thick salsa on each of them, sprinkle oat bran over that (it absorbs the moisture to keep the cracker from getting soggy), then shred one small cube of raw milk cheese over them, sea salt, lots of oregano. Then toast them at 350 degrees for about 4 minutes. Mucho yummy for breakfast or any time
But usually I have more breakfast-y foods--oatmeal, boiled egg, turkey bacon, etc.
