After a busy morning, lunch can feel like just the pick-me-up you need — but sometimes the meal you thought would energize you is the very thing that makes you want to nap at your desk.

Feeling tired post meals in general is known as the food coma.

Part of this phenomenon is due to basic physiology: When humans eat, most of our blood goes to the digestive organs to process the food, said Sandra Arévalo, director of community health and wellness at Montefiore Nyack Hospital in New York state.

The tendency to get tired after eating isn’t inherently suggestive of something amiss. But there can be additional factors that exacerbate this natural response. Here’s what to watch out for and how to make adjustments.

Heavy or sugary meals

A common cause for food coma is consuming meals that are heavy in terms of quantity or quality.

Some people overeat instead of stopping when they feel comfortably satiated. Not eating breakfast can also lead to overindulging later in the day if excessive hunger makes controlling your appetite difficult, Arévalo said.

Sometimes, however, the makeup of certain foods can contribute to tiredness. Fats are the hardest nutrient to digest because their molecules are much larger than those of protein or carbs, said Julie Stefanski, a spokesperson for the Academy of Nutrition and Dietetics. If you had a meal high in fat — such as fried foods or pizza — that could make you feel tired. Meals high in added sugar or refined or highly processed carbohydrates can have the same effect. “A five-minute walk or something helps to improve circulation and alertness, as well,” Arévalo said.

Poor sleep

Sleep regulates your hormones, including your digestive ones, according to Kristin Kirkpatrick, a registered dietitian at the Cleveland Clinic.

And if you’re sleep-deprived, your body’s likely to suppress the hormone called leptin that signals “I’m full and don’t need any more” or elevate ghrelin, the hormone that commands “feed me,” she explained. Being insufficiently rested can also negatively affect your decision-making skills, emotional regulation and a brain region that regulates food intake, making it harder to resist cravings for highly palatable foods.

Blood sugar issues

For some people, post-meal fatigue can signal something more serious.

According to Stefanski, when someone can’t properly metabolize carbs and therefore has a high amount of insulin in the blood, that can diminish energy levels.

Words to Learn 相关词汇

【加剧】jiājù exacerbate to make sth worse, especially a disease or problem

【睡眠不足 】shuì mián bùzú sleep-deprived not having had enough sleep for a peiord of time

在忙碌的早晨结束后，午饭是你所需的能量补给站，但是有时候这顿饭不仅没有像你想的那样让你重振精神，反而让你在办公桌前打起盹来。

吃完饭感到困倦俗称饭气攻心。

美国纽约州蒙蒂菲奥里·奈阿克医院社区卫生和保健部主管桑德拉·阿雷瓦洛指出，这种现象一部分是因为自然的生理反应：当人类进食时，大部分血液都流到消化器官去处理食物了。

吃完就犯困不一定意味着身体出了毛病，但是有一些因素会加重这种自然反应。来看看应该注意哪些因素，以及怎么做才能减轻饭后的困倦感。

油腻或高糖的饭食

如果你饭后觉得特别累，一个常见的原因是你吃得太多或太油腻。有些人吃饱了还吃，结果就吃多了。阿雷瓦洛表示，不吃早餐也容易造成午饭吃太饱，因为过饥会让你难以控制自己的食欲。

不过，有时候，特定食物的成分也会引起困倦感。营养与饮食学会发言人朱莉·斯特凡斯基指出，脂肪是最难消化的营养物质，因为脂肪分子比蛋白质或碳水化合物的分子大得多。如果你的餐食富含脂肪，比如油炸食品或披萨，你就容易感到困倦。阿雷瓦洛称：“散步5分钟之类的运动有助于改善循环，让你更清醒。”

睡眠不佳

克派崔克指出，睡眠能调节激素分泌，包括你的消化系统中的激素。她解释道，如果你睡眠不足，你的身体会抑制瘦素的分泌，这种激素会发出信号让大脑知道“我已经饱了，不用再吃了”，你的身体还可能增加胃饥饿素的分泌，这种激素会向大脑发出“喂饱我”的信号。睡眠不足还会给你的决策能力、情绪调节能力和调节食物摄入量的大脑区域带来负面影响，让你更难抵制美食的诱惑。

血糖问题

对有些人来说，饭后的困倦感可能意味着更严重的问题。斯特凡斯基表示：如果一个人不能很好地代谢碳水化合物，血液中会含有大量胰岛素，这会让人精力不济。(chinadaily.com)