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---------------- 1967 - Diet versus Exercise.
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- Some doctors went on an African safari to possibly learn some answers to the above questions. They tested African bush people who hunted giraffes for food. They were in the desert hunting with spears and dart blow pipes. The doctors were using sophisticated medical equipment including mass spectrometers. The could do scientific testing that compared primitive hunters to califonia couch potatoes.
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- To make these tests the patients were to drink expensive bottles of water enriched in rare isotopes, deuterium and oxygen-18. Analyzing their urine they would measure the daily rate of carbon dioxide production. Then calculate their daily energy expenditure, calories burned.
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- They accumulated a record of calories burned each day during their hunting expeditions. The conclusion surprised them: Humans tend to burn the same number of calories regardless how physically active they are.
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- At the same time modern humans have evolved to burn considerably more calories than their primitive ancestors, or other primates.
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- Why does the physical exercise not generally result in weight loss?
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- Energy is central to everything in biology. Calories in and calories burned. Metabolism , the sum of physical and chemical processes in the body.
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- Evolution, we turn energy into kids who use natural selection to gain maximum return on each calorie spent.
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- In the last 10,000 years humans have evolved from hunter - gatherers to couch potatoes with farming and cooking doing the real work. The standard thinking is the hunter-gatherers daily energy expenditures keeps them trim and fit. Couch potatoes with reduced energy expenditure turn unburned calories into fat. That was “ standard thinking”.
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- But, that is not what the isotope ratio mass spectrometer measurements told them.
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- Bush men burned 2600 calories a day, women 1900 calories per day.
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- California couch potatoes did the same. How is this possible? Physically active people burn more calories, right? Couch potatoes burn nothing TV watching.
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- But, these tests showed that populations coddled by the modern conveniences of the developed world have similar energy expenditures to those living in less developed countries living more physically demanding lives.
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- These same tests showed that monkeys, apes, lemurs as captured primates in labs and zoos expend the same number of calories as those in the wild. Sheep and kangaroos kept penned versus those that roam free. Giant pandas in the zoo versus those in the wild. Same result!
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- Comparing couch potatoes to those moderately active people used on average of only 200 calories less. What is going on to not have a greater difference?
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- The body adjusts to higher activity levels to maintain daily energy expenditures in check.
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- The body apparently makes up the difference in energy budget by reducing its house keeping chores that our cells and organs use to keep us alive. Saving energy on these processes make room for other activity.
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- Exercise reduces inflammatory activity that our immune system mounts as well as reproductive hormones such as estrogen. All this to keep our calorie count constant.
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- Daily active exercise will result in fewer ovulatory cycles and slower tissue repair.
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- Obesity is a disease of gluttony rather than a lack of exercise We gain weight when calories consumed exceed calories expended.
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--------------------- “ You can’t out run a bad diet” --------------------
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- However, it is not just weight that you should be concerned about. Exercise improves your heart and your immune system. Exercise keeps you healthy. Diet alone can keep the weight off.
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- Rabbits reproduce prodigiously but die young. Investing in one trait means investing less in another.
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- Our brains are comparatively so large as to consume 25% of our oxygen. Every 4th breath you take goes to feed your brain. Yet, humans have bigger babies, live longer, and are more physically active than our ape relatives.
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- Humans consume and expend 400 more calories daily than chimpanzees. Our digestive tract is smaller and less costly than that of apes. Apes need more in order to digest fibrous, plant based diets.
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- Humans are the only species that has learned to cook. This alone greatly increases the calorie value of food. It becomes much more efficient to digest.
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- Fat evolved as a critical energy buffer to survive lean times. If your times are not lean you don’t need it. Loose it.
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- Hunter-gatherers who lead physically active lives burn the same number of calories as us couch potatoes. Human’s metabolic engine has evolved to support our costly brains. Think about it. Food for thought.
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- Note (1): Request any of the Reviews by number to learn more.
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----- 707-536-3272 ---------------- Thursday, April 6, 2017 -----
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