Over the holiday weekend, we had a houseguest who was in the middle of a weight-loss program. She had joined a national weight- loss group and was very pleased with her results. Not only had she lost six pounds in under six weeks, but as she told us, her food choices were much more sensible and no longer impulsive.However, as the weekend proceeded, I noticed that every afternoon she would wander around the kitchen looking hungry. But when I offered her a variety of healthy snacks, the only food she would eat was fruit. And then she would eat so much I wondered how her digestive system was handling it.In what I hoped was a subtle discussion of her weight-loss program I asked how fruits fit into its caloric structure. “We are allowed to eat a lot of fruit because they are low in points,” she told me. “ I think I may overdo it but I feel hungry every afternoon and I don’t know what else to eat. I don’t want any yogurt or salad and even protein bars don’t satisfy me. In fact, I am wondering how much longer I can stay on this diet if I can’t get rid of this hunger.”She went on to say that her hunger was different from being hungry at mealtime. “The funny thing is that there is plenty of food on the diet and most of the day I am really full. But there is something about the afternoon that starts me daydreaming about eating cookies or a piece of chocolate. I asked the group leader about this and she just told me to eat fruit as an afternoon snack. But no matter how much fruit I eat, I still feel hungry for something sweet. It’s crazy.” I laughed and told her that she wasn’t crazy. She was simply experiencing a natural afternoon craving for carbohydrates that she probably had all her life.“You are right,” she answered. “I always ate something sweet or starchy around 4 pm. But I assumed that was why I had gained weight. So I decided not to give into myself once I started the diet. But now I am worried I am not going to be able to stay on the diet much longer. I have 5 more pounds to lose but if I don’t do something about this hunger, I am not going to make it.”I asked her if there was any reason why she couldn’t eat a sweet or starchy food around 4 pm and she told me she could eat anything she wanted as long as she didn’t go over her points. We were having this conversation late in the afternoon so I offered her some low-fat sweet crunchy breakfast cereal as a snack.“Have about 2/3 rd of a cup because that will be the same number of calories as two small pieces of fruit,” I suggested.” You will feel full about 10-15 minutes after you finish.”“Why would the cereal work better than fruit to take away my hunger?” she asked. I explained that serotonin, the brain chemical that controls our mood, also shuts down our appetite. Sometimes, especially late in the afternoon, our brains need to make more serotonin and we feel a need to eat sweet or starchy carbohydrates as a result. The connection between carbohydrates and serotonin is through insulin. When starchy or sweet carbs are eaten and digested, insulin is activated and this leads to the amino acid tryptophan to get into the brain. As soon as tryptophan enters the brain, new serotonin is made.” “So why does my eating this cereal have an effect on my appetite?”“Serotonin seems to be the switch that turns off our appetite,” I told her. “ You will see. Very soon you are going to feel very content and satisfied.” “You mean serotonin works like an appetite suppressant?” she asked. “So why do I still feel hungry after eating fruit?” The problem with fruit, I told her, is that no insulin is released after it is eaten. So no matter how much fruit you eat to take away your sweet cravings, you will still have them. I went on to say that fruit is still an important part of her diet but she was just wasting her points by eating fruit to stop her afternoon hunger. But any starchy or sweet food like pretzels, popcorn, sweetened breakfast cereal or even honey and toast will get the body to make serotonin. She just had to make sure that the carbohydrate did not contain much protein.“When you eat protein, either with the carbs or right before you have a carbohydrate food, no serotonin is made. And obviously eat carbs that are very low in fat like this breakfast cereal. You don’t need to add those calories or points or whatever to your diet. By the way, are you still hungry?”She smiled. “You know, for the first time since I started this diet program, I don’t have the afternoon munchies. I can’t believe just eating this small bowl of cereal filled me up so much.”“ Well,” I answered, “thank your serotonin. “
