Extended guts are generally due to the enlarged liver. We see it in the alcoholic "beer belly" effect. We see it in the malnourished tribal children who eat toxins. We see it in the patient who consumes toxic prescription medications several times a day, etc. The liver filters toxins, and when a larger than average amount of toxins are presented to the liver, it will grow in size and regenerate. The liver, which filters toxins to be excreted through the intestines, will also produce gall stones which will also increase the size of the liver. When the liver enlarges in size, it will push against the intestines, because the liver is on your right side, next to your intestines. As the liver grows in size, it will push against your intestines, and the organs will extend. Body builders 50 years ago, like Arnold, rarely had extended abdomens because they lacked high amounts of processed foods, preservative chemicals, and the vast amount of toxins today. Back then, they ate fresh garden veggies all the time because they didn't even have microwaves. Best liver detoxifiers include the grapefruit and lemon. Dieters would consume the grapefruit and lose weight because they would detox the liver and help remove gall stones. And, when the liver shrank, so did the "extended abdomen." Lemonade is given during the summer, because a toxic enlarged liver will cause the body to sweat a lot more. People often would put real lemons into the lemonade so that the consumer would know its not kool aid or fake lemonade. This is because the lemon juice is very powerful to detox the liver, similarly to the grapefruit.
To conclude, bodybuilding competitors on stage today generally have an increased level of extended abdomens due to the American food and dietary changes over the past 50 years. Over this period of time, gardens of fresh fruits and veggies have diminished significantly, and the microwave has been introduced, which will kill the nutrition that would detox your liver. One could easily conclude that the best liver detoxifiers are fruits and veggies. And, that gardens have diminished in popularity significantly, and that, although fruits and veggies from a garden would be free. They'd rather fo to McDonalds. It just feels to me that, since the world population has mxed out past the level of resource allowances, (more population than resources could keep up with), that the planet is making our lives more difficult to have and survive. For example, over the years, the world leaders take away our rights through laws to prevent our freedom that we used to have. "Its a free country" slogan is now nonexistant. Also, our nutrition that we need to be healthy and happy is diminshing as we are switching to GMO genetically modified foods and our garden veggies are now lacking nutrients as they come prepared in cans now, sprayed with chemicals, genetically modified etc. This would allow one to conclude that we must do even more research so that our population, environment, and planet doesn't try to swallow us up whole and that we are able to continue to enjoy our lives.