The conventional wisdom is that carbohydrate is easier to burn up than fat in the body. When taking exercises, the body takes carbohydrate first as energy source rather than fat. So, for the demand of taking exercises, the athletes are usually advised to take foods of high
carbohydrate and high protein. I looked for on internet Michael Phelp's diet, I cite it below for your reference. You will find they are carbohydrate and protein mainly.
Here's Phelps's typical menu. (No, he doesn't choose among these options. He eats them all, according to the Post.)
Breakfast: Three fried-egg sandwiches loaded with cheese, lettuce, tomatoes, fried onions and mayonnaise. Two cups of coffee. One five-egg omelet. One bowl of grits. Three slices of French toast topped with powdered sugar. Three chocolate-chip pancakes.
Lunch: One pound of enriched pasta. Two large ham and cheese sandwiches with mayo on white bread. Energy drinks packing 1,000 calories.
Dinner: One pound of pasta. An entire pizza. More energy drinks.
The article I found on internet published this Phelps' menu, there is also a warning on the top, "Don't try it at home!" From a typical Phelps' menu, you can easliy find out what makes a world-class athlete.
Although the report said cabo consumption contributes to risk factor to certain disease, if only the Chinese translation is read you might think so. The conclusion in the original report quoted
過去，人們總認為脂肪是導致肥胖的元凶，但越來越多營養學家把矛頭指向碳水化合物。他們認為，減少攝取碳水化合物才是有效降低肥胖、心臟病、第二型（成人型）糖尿病及高血壓的關鍵。
哈佛大學公共衛生學院營養學系主任威列特博士（Water Willett）表示：「如果美國人去除含糖飲料、馬鈴薯、白麵包、麵條、白米與含糖零嘴，就可徹底解決因體重、糖尿病、代謝疾病引發的相關問題。」
美國人平均每天攝取二五○至三○○公克碳水化合物，占每日攝取熱量的五五％，最保守的建議攝取量是一二五至一五○公克。卅年來，美國政府積極推廣減少脂肪攝取，以致碳水化合物消耗量遂逐年增加，肥胖、心血管疾病及第二型糖尿病的病例跟著上揚。
加州大學戴維斯分校營養生化學家費尼（Stephen Phinney）指出，身體厭倦處理高量碳水化合物時，可能改會變對胰島素的反應，演變為「胰島素抗性」，其徵兆包括代謝症候群、高三酸甘油酯、高血壓、腹部肥胖、好膽固醇濃度低或空腹血糖過高等。在美國成年人當中，有三種以上症狀者了占四分之一。
費尼在二○○八年發表的報告中，以四十名過重或肥胖者進行實驗，所有人每天攝取一千五百大卡熱量，一半採低脂高醣飲食，其餘為低醣高脂。十二周後，低醣高脂組的三酸甘油酯濃度下降五○％，好膽固醇上升一五％；低脂高醣組的三酸甘油酯僅下降二○％，好膽固醇濃度不變。
費尼指出：「碳水化合物是威脅人體代謝的惡霸，它們搶在脂肪前面，硬要頭一個被燃燒，沒被燃燒的部分成了脂肪，只要有碳水化合物在，囤積的脂肪就一直堆在人體內。」
Carbohydrate reduction reverts obesity and more
Counting calories the essential to a diet. How many people have stop and think about the carbohydrates in their diet.
Topnutritional scientists state that carbohydrates are the culprit and notfor the cause of health conditions in Americans. Scientists are statingthat by decreasing the intake of carbohydrates in a diet is theessential element to reverse obesity, heart disease, Type 2 diabetes and hypertension.
Dr.Walter Willett, chairman of the department of nutrition of the HarvardSchool of Public Health, comments that fat is not the issue. IfAmericans would eliminate sugary beverages, white bread, pasta,potatoes, white rice and sugary snacks, nearly all the issues of healthwould be eradicated in the area of weight, diabetes and metabolic diseases.
Dr.Edward Saltzman, associate professor of nutrition and medicine at TuftsUniversity, comments that is a complicated message. For a lot of yearsAmericans have been told that the consumption of fat would make you fatand lead to the development of chronic illnesses. Dietary fat was knownas public enemy number one. Now a expanding and established grouping ofscientists are now laying blame on carbohydrates, especially thosefound in refined sugar and flour.
On the average most Americans consume 250 to 300 grams of carbohydrates each day.This accounts for around 55% of their total calorie intake. The mostmoderate recommendations indicate half of that amount for consumption. Carbohydrate consumption has increased over the past few years with aide from the government authorized message to cut fat.
Obesityis on the up rise in Americans along with Type 2 diabetes and heartdisease. According to Dr. Frank Hu, professor of nutrition andepidemiology at the Harvard School of Public Health, remarks that thecountry's immense message of low fat has failed. By overstating fat reductioncreated the consumption of carbohydrates and sugar in diets toskyrocket. This change could be associated to the biggest healthproblems in Americans today.
Why this new dietary shift
Carbohydrates including sugar change into sugar in the blood and the morerefined the carbohydrates are faster the change occurs. Upon consuminga glazed doughnut quickly the doughnut turns into blood sugar. Tocontrol blood sugar, the pancreas makes insulin, which sends sugar intocells, where it is kept as fuel in the form of glycogen.
Even ina totally healthy metabolism. The body over a period of time becomestired of processing high amounts of carbs, which are bodies were notdesigned for causing the body's response to insulin to alter. Accordingto Dr. Stephen Phinney, nutritional biochemist and emeritus professorat the University of California. Dr. Phinney has studied carbohydratesover thirty years.
As cells become more resistant to instructions from insulin, the pancreas must produce more insulin to push the amount of glucose into the cells. When people become insulin resistant, carbohydrates become moreof a challenge for the body. When the pancreas becomes tired and cannotmake insulin to maintain glucose in the blood, the development ofdiabetes occurs.
Insulin resistance first warning sign is metabolic syndrome, a major warning that diabetes andthe possibility for heart disease is near. The syndrome is thought tooccur when people have three or more of the following: high blood triglycerides (more than 150 mg); high blood pressure (over 135/85); central obesity (a waist circumference in men of more than 40 inches and in women, more than 35 inches); low HDL cholesterol (under 40 in men, under 50 in women); or elevated fasting glucose.
triglyceride【化】三酸甘油酯
High-density lipoprotein (HDL) 高密度脂蛋白 High-density lipoprotein (HDL) is one of the five major groups of lipoproteins which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL and HDL, which enable lipids like and triglycerides to be transported within the water-based bloodstream. In healthy individuals, about thirty percent of blood is carried by HDL.
cholesterol 膽固醇
Around one-fourth of American adults have these symptoms.
Dr. Phinney states if you place those people on a low-carb diet not only will they have weight loss but blood levels will show improvement. In a study done in 2008, conducted by Dr. Phinney and associates involving 40 overweight or obese men and women with metabolic syndrome were placed on a 1,500 calorie diet. Twenty were on low-fat high-carb diet. The other twenty low-carb high-fat diet. Low fat group had consumed 12 grams of saturated fat each day out of 40 grams of fat. Low-carb group consumed 36 grams of saturated fat daily.
Even with all the added saturated fat the low-carb group at the end of the twelve week study had shown a 50% decrease in triglycerides levels (risk factor for heart disease) and (good) cholesterol increased by 15%.
The conclusion in this study with several others show that dietary fat consumption is not directly associated to blood fat. It appears that carbohydrates in the diet is the main contributor.
Dr. Willett remarks that there is good news. Based upon the knowledge acquired, nearly all Americans could avoid Type 2 diabetes. Eliminating unhealthy carbohydrates is the key. For people just diagnosed, a low-carb diet takes the strain off the pancreas before damage can occur while improving the condition by either decreasing or avoiding the need for insulin and other diabetic medications.
The opposition on this theory
Not all scientists of nutrition are totally behind this new idea.
Dr. Ronald Krauss, senior scientist at Children's Hospital Oakland Research Institute and founder along with past chair of American Heart Associations Council on Nutrition, Physical Activity and Metabolism, states in a general tense he does agree with promoting fewer carbohydrates but does not like to lay blame on one food group.
Dr. Krauss states that consumption of too many calories lead to over-consumption of carbohydrates. It can be greatly valuable to limit the carbohydrate intake and use protein and fat for a substitute. However, in general he is not recommending extreme dietary measures for health promotion.
Professor Joanne Slavin, professor of nutrition at University of Minnesota and member of the advisory committee for the 2010 Dietary Guidelines for Americans,is less swayed to support this movement. Professor Slavin states that the committee had looked at carbohydrates and health results and did not find any proof of a association between carbohydrate consumption and risk for disease.
Professor Slavin notes that most Americans need to reduce calories and increase physical activity. Reducing carbohydrates is a good idea, "but making a hit list of carbohydrate-containing foods is shortsighted and doomed to fail, similar to the low-fat rules that started in the 1980s."
It appears the verdict on this new theory is still out and the 2010 Dietary guidelines for Americans will still stand in place as is atleast for now.
