You: On a Diet: The Insider’s Guide to Easy and Permanent Weight Loss. Michael Roizen F.

      Once it reaches the bloodstream, food continues to influence how hungry you may feel. Elevated blood sugar sends your brain the message that it’s time to take your plate to the sink and hit the couch. When your blood sugar is low, that’s what stimulates hunger and causes you to feed like a rat in the Kraft aisle.

      Many of us get into trouble when we eat foods with simple sugars (think soft drinks, jelly, cake). Simple sugars create a rebounding effect. You’re feeling blah, so you eat a 3 Musketeers. That sugar surge works like an electrical jolt, and you instantly feel more energy. But less than two hours later, that energy surge (in the form of elevated blood sugar levels) plummets, and then you feel blah again. Your conclusion? You must need another Musketeer. That rebound effect (combined with the desire for the taste that’s stimulated by the pleasure center in your brain) can put your body in biological turmoil, where you eat to feel better, though what you’re eating is actually making you feel sluggish, so you swirl and swirl around, always feeling like you need to eat.

      The Word on GERD

      Fat doesn’t just pose problems for your belly and subway turnstiles; it also can mess with your throat. About half of obese people have the chest-burning condition called GERD (gastroesophageal reflux disease). The thinking is that extra fat in the belly pushes down on your stomach, thereby opening the angle of the GE junction and pushing it toward the chest. (Remember, it’s at an acute angle to keep food from going back up your throat every time you eat.) The pried-open angle makes it easier for acid and food to be pushed back up. Plus, the extra fat in the belly puts pressure on the contents of your bowel. More pressure, more GERD. What’s the big deal? Besides the unpleasant sensation of tasting your food on the way up, GERD also burns your esophagus-in the same way that the sun burns your skin. After a burn, it takes a couple days to heal, but if the burning happens over and over, it means you’re burning the tissues and are more likely to develop cancer there, just like repeated sunburns increase your risk of skin cancer. Taking half a full aspirin or two baby aspirin (you want 162 mg) with a glass of water decreases this risk by about 35 percent. By the way, alcohol, coffee, pepper, acidic foods like tomatoes and OJ, and, to a lesser degree, chocolate increase GERD symptoms. The best way to manage symptoms until you lose weight is to avoid meals within three hours of bedtime and to put blocks under the head posts of your bed so that you sleep at a slight tilt. (Pillows usually don’t work, since your head will typically roll off the pillow.)

      YOU-reka! At the bottom end of your small intestine (before it joins your large intestine), food hits the ileal brake—another signal that you’re full. At this juncture there’s a traffic signal that slows the passage of the slurry of intestinal contents from the small intestine to the large intestine. It’s called the ileocecal valve. The squeezing required to overcome this traffic signal valve is reduced naturally by some foods, since your body feels that you’re still digesting and not ready to evacuate those foods yet. Very little absorption of nutrients occurs in the colon, so once the food passes the ileocecal valve, not much more happens except that you reabsorb water while consolidating the waste you’ve formed. The result: You have a traffic backup in your gut, and if you try to send more cars down the road, the problem’s only going to turn into a fuller feeling. It’s one of the reasons why fiber kills cravings, because fiber slows down the transit of food from your small intestine to your large intestine, keeping that full feeling. In the next chapter, we’ll pick up the rest of the digestive journey in the intestines, where some of the key fat-storing processes take place.

      Figure 3.6 Acid Trip Fat presses on the gastroesophageal junction and unkinks this connection, which makes acid and reflux move up toward the throat. Pressure on the stomach from intra-abdominal fat increases the backwash.

      The System of Satisfaction

      Though it may seem that we have endless reasons to eat-to celebrate holidays, to beat stress, to pass time between Super Bowl commercials-there’s only one real reason why we need food: for energy. That energy allows our organs to function, our muscles to move, and our bodies to keep warm. And to a large extent our brains help control how we convert food to energy. To help understand the process that your body goes through to use energy, we’ll break down the metabolic path into two phases.

       Digestive Phase: Your hypothalamus orchestrates this phase of metabolism by receiving signals from throughout your body about whether you’re hungry or not so that your body can use energy to power itself. Here’s how: Your body has a short-term reservoir for energy in the form of glycogen, a carbohydrate primarily stored in your liver and muscles. After eating, when you have glucose (sugar) and insulin (the hormone produced in the pancreas to transport glucose), your body uses all of the glucose it needs for immediate fuel but takes the rest and stores it as glycogen. If your blood glucose level falls, your pancreas stops releasing insulin-and then releases another G substance, glucagon, which converts the stored energy (glycogen) to sugar (glucose). So the effect is that when your intestinal gas tank empties of sugar (in other words, when our ancestors were fasting between bison hunts), your body is still able to supply crucial energy to your central nervous system by converting glycogen to glucose.

       Fasting Phase: When you’re sleeping or go long periods without eating, your body needs to have a supply of energy to keep your organs functioning. Once you use up all of your available glucose during the digestive phase of metabolism (your body stores only about 300 calories in the short-term glycogen reservoir), it taps a long-term reservoir: fatty tissue in the form of triglycerides (molecules that include a carbohydrate-containing glycerol). This keeps you going until you break the fast with breakfast.

      Figure 3.7 First-degree Burning Feasting allows our livers to store excess sugar as glycogen, so we can access energy without eating for hours. Once glycogen stores are full we save the excess energy from an ice cream sundae as fat. To break down fat we first have to use up glycogen, which can take a half hour of exercise. That’s when the body automatically begins burning up fat.

      YOU TIPS!

      Slow the Process. Especially before your meal. If you have a little of the right kinds of fat just before you eat you can trick your hormonal system by sending the signal to your brain that you’re full. If you eat a little fat twenty minutes before your meal (70 calories or so of fat in the form of six walnuts, twelve almonds, or twenty peanuts), you’ll stimulate production of CCK, which will both communicate with your brain and slow your stomach from emptying to keep you feeling full. (CCK release and ghrelin reduction take about twenty minutes to kick in and take about 65 calories of fat to stimulate.) That way, you’ll be able to sit down for a meal and eat for pleasure, not for hunger-which is one way to ensure you’ll eat less. The average person is finished eating well before his satiety signals kick in, thus counteracting any possibility that his hormones can help him. For the same reason, you should eat slowly. If you down your food faster than a MiniVac, you won’t allow your satiety hormones time to kick in.

      Set the Early Fiber Alarm. Many of us may associate fiber with better health and increased toilet time, but fiber is the speed bump of your GI interstate. It slows everything way down. Technically, it works by slowing the transit of food across the ileocecal valve, keeping your stomach fuller for longer. The result: a greater feeling of satiety and an increase of appetite-suppressing CCK-like signals. While you should aim for around 30 grams of fiber a day, the key is bulking up in the morning. Studies show that consuming fiber in the morning (at breakfast) makes you less hungry in late afternoon-a notorious candy-sucking, diet-busting time of day. Great sources of breakfast fiber include oatmeal, cereal, whole grains, and fruit. (You’ll note that every breakfast in the YOU Diet-see Part 4-has a lot of fiber in it, whether it’s the cereal or the vegetables in an egg white omelet or the whole wheat bread. And morning snacks, like an apple, also have fiber.)