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Fruit: Fads, Digestion and Cleanses

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These days, the Internet provides us with news on the latest fad diets and health trends. On top of these headlines, we receive emails with drastic nutrition recommendations. One of these chain emails describes eating fruit on an empty stomach for proper digestion. It declares that, "Eating fruit after a meal causes the whole meal to rot and ferment. The minute the fruit comes into contact with other food in the stomach and digestive juices, the entire mass of food begins to spoil." It then says, "If you should drink fruit juice, drink it mouthful by mouthful slowly, because you must let it mix with your saliva before swallowing it." These incorrect statements really get to me.

This information alludes to the bestselling book, "Fit For Life," written by Harvey and Marilyn Diamond. Their theory emphasized "food combining" and improper blends of foods that cause rotting and malabsorption in the gut. They state that if fruit is eaten with or after other food, it releases toxins and leads to heartburn and discomfort. According to this fad diet, combining starches and proteins together mixes acids and bases in your stomach to inhibit digestion.

These claims are absolutely untrue. Digestion is a process specific to each macronutrient. Eating different types of food together will not inhibit the digestion of separate items or cause rotting or fermentation. Dr. Pochapin, director of the Monahan Center for Gastrointestinal Health at New York-Presbyterian Hospital/Weill Cornell Medical Center, explains this:

Rotting or fermentation means bacterial action on food resulting in decomposition. And because of the presence of hydrochloric acid, the stomach has very few bacteria... Food takes six to 10 hours to reach the colon, which explains why it does not really matter when fruit is eaten.

All food is broken down and metabolized through specific steps.

To prove this point, let's take a quick, simplified look at digestion:

1. Carbohydrate digestion begins in the mouth with salivary enzymes. As carbohydrates reach the stomach, digestive acids churn and mix with the molecules. The next step occurs in the small intestine where pancreatic amylase breaks down the larger chains into monosaccharides (simple sugars). These small molecules can then be absorbed into the bloodstream. Insulin, secreted by the liver, regulates blood glucose levels and distributes glucose to the body, where it can be used for energy or stored.

2. Protein digestion, a more time-consuming process, begins in the stomach when hydrochloric acid and pepsin, a gastric enzyme, begin breaking down peptide bonds. Next, the smaller proteins move into the small intestine, where pancreatic enzymes, trypsin and chymotrypsin, continue the breakdown of proteins into amino acids. These smaller units are then absorbed into the bloodstream and distributed to body tissues.

3. Fat digestion slowly begins in the small intestine. Since fats don't dissolve in water, they require an extra step. Bile, produced by the liver, is released into the small intestine to dissolve fat into droplets. This allows pancreatic and intestinal enzymes to break the large fat molecules into smaller molecules. These smaller molecules are formed into micelles -- units that can be absorbed into the lymphatic system. These fatty acids are eventually sent into the blood stream and travel to fat cells or muscle cells to be stored or used for energy.

These actions work simultaneously with every combination of foods that we eat. Pairing certain foods together actually keeps us feeling full longer. Adding a small amount of protein or fat with fruit or a simple carbohydrate will slow down digestion, as protein and fat take longer to move through our digestive system. This doesn't mean that food sits and rots in your stomach; everything continues as usual.

Lastly, the email praises juice cleanses. To purify our bodies, the chain email states, "Eat fruit and drink juice for just three days, and you will be surprised when friends say how radiant you look!" A juice cleanse may give a "radiant" glow for the first day, but it tends to have a negative effect on the body. People believe cleanses clear out harmful built-up toxins. Our liver, kidneys and digestive system rid our bodies of "toxins" on a daily basis by their normal functions! Also, losing weight by cleansing doesn't lead to long-term healthy results. Instead of shedding excess fat, weight loss is temporary. A permanent weight reduction may be due to muscle mass loss, as the body breaks down its own muscle tissues due to lack of protein intake.

According to Marc Hellerstein, M.D. Ph.D, professor of human nutrition at the University of California at Berkeley, "Your body thinks you're starving and panics. Your metabolism slows way down to preserve your muscle and basic bodily functions." After most people start eating normally again, they tend to gain the weight back very fast!

Most health trends regarding fruit just don't add up. Eat fruit in proper portions with or in-between meals. Digestion occurs as normal no matter when you add fruit to your diet. A juice cleanse may actually inhibit normal digestive cycles, instead of giving long term results. As always, being portion savvy is key.

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