밥과 과일, 다이어트에 더 큰 적은?

과일이다

과일에는 살을 찌게하는 '과당' 많이 함유

쌀밥의 주성분은 포도당

Tip

보통 과일 후식을 식사 후 하는 경우가 많은 데  다이어트를 위해서는

먼저 먹는 것이 좋다. 왜냐하면 포만감때문에 식사를 적게 할 수 있기때문이다.

edited by kcontents 

케이콘텐츠 편집

칼로리를 제한하며 다이어트를 해도 살이 빠지지 않는다면 섭취하는 당의 양을 체크해 봐야 한다는 연구 결과가 나왔다.   미국 서던캘리포니아 연구팀은 칼로리가 동일한 당인 과당(fructose)과 포도당(glucose) 중 과당이 더 살을 찌운다고 ‘미국 국립과학원회보(PNAS)’ 4일자에 발표했다. 과당은 과일 등에 많이 들어있는 당이며, 포도당은 쌀밥의 주성분이다.   istockphoto 제공 연구팀은 실험 참가자 24명에게 하루는 포도당이 75g 들어있는 음료를 먹이고, 또 다른 날은 같은 양의 과당이 들어있는 음료를 먹인 뒤 사람들의 반응을 비교했다.   고칼로리 음식을 보여주고 실험 대상자들의 뇌 반응을 기능성자기공명영상(fMRI)으로 촬영하자 과당을 섭취했을 때 안와 전두피질(orbital frontal cortex)과 시각피질(visual cortex)이 특히 활성화되는 것으로 나타났다. 과당을 섭취했을 때가 포도당을 섭취했을 때 보다 음식에 더 적극적인 반응을 보인다는 의미다.   이전 연구에서는 과당이 포도당보다 식욕을 덜 억제한다는 결과가 보고 된 적이 있다.        연구팀은 또 과당과 포도당을 섭취했을 때 인슐린의 분비 정도를 측정했다. 그 결과 과당을 섭취했을 때는 포도당을 섭취했을 때 보다 인슐린 분비량이 절반가량으로 줄었다. 인슐린이 잘 나오지 않는 만큼 체내 혈당은 높게 유지된다.   연구팀은 두 당을 섭취했을 때 뇌와 호르몬의 다르게 반응하는 이유를 두 당의 대사과정이 다르고 여기서 나오는 중간대사물 역시 차이가 나기 때문이라고 추측하고 있다.   연구팀은 “앞으로 두 당의 인슐린 저항성 차이가 뇌에 어떻게 영향을 미치는지를 알아볼 것”이라고 밝혔다. 동아사이언스 신선미 기자 vamie@donga.com

Fructose may increase cravings 

By The New York Times , Herald-Tribune  The type of sugar you eat may affect your cravings for high-calorie foods, researchers report. An experiment with 24 healthy volunteers found that compared with The type of sugar you eat may affect your cravings for  high-calorie foods, researchers report.  (New York Times photo) consuming glucose, consuming fructose — the sugar found in fruits, honey and corn syrup — resulted in more activity in the brain’s reward regions, increased responses to images of food and a tendency to choose eating a high-calorie food over a future monetary reward. The volunteers drank a 10-ounce glass of cherry-flavored liquid that contained two and a half ounces of fructose or glucose. (Table sugar, or sucrose, extracted from sugar cane or sugar beets, is a compound of glucose and fructose.) Researchers also took blood samples to measure levels of glucose, fructose and insulin, and of leptin and ghrelin, enzymes involved in controlling hunger and feelings of fullness. Before having their drinks, the participants rated their desire to eat on a one-to-10 scale from “not at all” to “very much.” Then they drank the liquids and had functional magnetic resonance imaging brain scans while looking at images of food and of neutral objects like buildings or baskets. As they did so, they rated their hunger using the scale. The volunteers were then presented with images of high-calorie foods and asked whether they would like to have the food now, or a monetary award a month later instead. The study, published in the journal PNAS, found that compared with glucose, consuming fructose produced greater responses to food cues in the orbital frontal cortex of the brain, a region that plays an important role in reward processing. The fructose drink also produced greater activity in the visual cortex when volunteers looked at images of food, a finding that suggests increased craving compared with glucose. When choosing between tasty high-calorie food or a delayed monetary reward, fructose drinkers were more likely than glucose drinkers to choose the food. There was no difference in leptin or ghrelin levels between fructose and glucose drinkers. But plasma insulin response was sharply lower in fructose drinkers, which may affect what we eat, according to the senior author, Dr. Kathleen A. Page, an assistant professor of clinical medicine at the Keck School of Medicine of the University of Southern California. “Insulin is released when we consume glucose,” she said. “The pancreas secretes insulin, and insulin drives glucose into cells so that it can be used for energy. But it also sends a signal to the brain that says ‘you’ve eaten.’ Fructose doesn’t stimulate insulin secretion, and if there’s no insulin, you don’t get the information that you’re full.” Does this mean that it is a good idea to avoid fruit, because it contains fructose? “No,” Dr. Page said. “Don’t stop eating fruit. It has a relatively low amount of sugar compared with processed foods and soft drinks — maybe 5 grams in an orange, compared with 25 grams in a 12-ounce can of soda. And it is packed with fiber, which helps slow down the absorption of food, which makes you feel full.” http://health.heraldtribune.com/2015/05/04/fructose-may-increase-cravings

edited by kcontents

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