减肥不吃主食？医生：或导致大脑功能衰退

在我们的日常饮食中米、面这些主食是必不可少的，“主食吃太多是变胖、导致糖尿病的元凶”这种说法最近越来越多。不吃主食真的不会影响身体健康吗？我们到底应该如何科学吃主食？  

In our daily diet, staples like rice and noodles are essential. There's a growing concern about claims that excessive staple consumption leads to weight gain and diabetes. Does cutting out staples have a positive impact on health? How should we consume staples in a balanced way?

长期不吃主食有何危害？

2023年3月5日，加拿大圣保罗医院、不列颠哥伦比亚大学的研究人员在《美国心脏病学会》年度科学会议和《世界心脏病学》大会上发表了一项新研究。研究发现，生酮饮食会引起“坏”胆固醇水平升高，从而增加2倍心血管疾病风险，包括心血管事件、心脏病发作和中风的风险。

The study revealed that the ketogenic diet can result in an increase in 'bad' cholesterol levels, subsequently doubling the risk of cardiovascular diseases, including cardiovascular events, heart attacks, and strokes.

 ketogenic diet/ keto diet：生酮饮食

 cholesterol levels：胆固醇水平

 cardiovascular diseases：心血管疾病

Notes

生酮饮食

这是一种低碳水化合物、高脂肪的饮食模式，旨在诱导人体进入生酮状态，其中身体主要依赖脂肪作为能量来源，而不是碳水化合物。这种饮食方式常被用于减肥、管理糖尿病和其他健康问题。

The ketogenic diet is a dietary approach that emphasizes high-fat and low-carbohydrate intake. Its primary goal is to induce a metabolic state known as ketosis in the body. During ketosis, the body shifts from burning its primary energy source from carbohydrates to fats.

在平均12年的随访期间，9.8%的不吃或少吃主食的参与者经历了新的心血管疾病，而标准饮食的参与者为4.3%，不吃或少吃主食的参与者的风险增加了1倍。

如果长期不摄入主食，碳水化合物摄入不足，机体要维持血糖的稳定，就要通过脂肪或蛋白质来进行转化，这样会给机体带来一定的副作用，比如说代谢紊乱。通过脂肪来供能会产生酮体，长期酮体的蓄积对身体会有不利影响。如果通过氨基酸来补偿，就会造成机体的瘦组织分解，时间长了会造成营养不良。

If you consistently avoid consuming staple foods and have insufficient carbohydrate intake, your body will need to convert fats or proteins to maintain stable blood sugar levels. This can lead to certain adverse effects on the body, such as metabolic disruptions. 

Utilizing fats for energy production generates ketones, and the prolonged accumulation of ketones can have detrimental impacts on the body. Compensating with amino acids can result in the breakdown of lean tissue in the body, potentially causing malnutrition over time.

staple foods：主食

carbohydrate [ˌkɑːrboʊˈhaɪdreɪt]：碳水化合物

metabolic disruptions：代谢紊乱

malnutrition [ˌmælnuˈtrɪʃn]：营养不良

而实际上，机体中有一部分脑组织还有红细胞，只能通过葡萄糖来供能，这个时候如果血糖不能保持稳定，会造成情绪低落、易怒、烦躁等情况。大脑每天需要130克淀粉来提供能量，如果长期不吃主食会造成大脑功能衰退，所以长期不吃主食这种做法是不对的。   

In fact, certain brain tissues and red blood cells in the body rely solely on glucose for energy supply. When blood sugar levels are not maintained steadily, it can result in symptoms such as low mood, irritability, and restlessness. 

The brain requires a daily intake of 130 grams of starch to fuel its energy needs. Prolonged avoidance of staple foods can lead to a decline in brain function. Therefore, the long-term avoidance of staple foods is not a recommended practice.

glucose [ˈɡluːkoʊs]：葡萄糖

low mood, irritability, and restlessness：情绪低落、易怒、烦躁

常见的主食有哪些？

     

我国常见的主食有粮谷类和薯类，杂豆类也常常作为主食的补充。

▌粮谷类：又可分为主粮和杂粮，主粮主要为稻米（南方）和小麦（北方），杂粮主要有玉米、小米、高粱、荞麦、燕麦等。

▌薯类：包括马铃薯、番薯（地瓜）、木薯、山药等。

▌杂豆类：主要有绿豆、红小豆、芸豆、花豆、蚕豆、豇豆等。

In China, our staple foods typically encompass cereals and root vegetables, with miscellaneous legumes often playing a supplementary role.

Cereals: This category can be further classified into staple grains and miscellaneous grains. Staple grains mainly include rice (in the southern regions) and wheat (in the northern regions), while miscellaneous grains comprise crops such as corn, millet, sorghum, buckwheat, and oats.

Root Vegetables: These include potatoes, sweet potatoes (yams), cassava.

Legumes: The primary varieties encompass green beans, red beans, soybeans, lima beans, fava beans, and cowpeas.

这一类食物主要为人体提供的是碳水化合物，是身体中主要供能的三大营养素之一，每天我们通过碳水化合物来摄取的热量应该占50%～55%，所以我们称它为主食。

主食这样吃才健康

 

➀ 巧搭配

粗杂粮包括玉米、燕麦、荞麦，以及杂豆类的红豆、绿豆、芸豆，还有马铃薯等，这些食物血糖生长速度比较慢，同时又富含蛋白质、微量元素、维生素，是比较优质的主食选择。

我们主张主食的选择应该粗细搭配，同时兼顾食物的多样性，所以咱们选择主食的时候应该种类尽量多。

We recommend a balanced combination of staple foods, incorporating a variety of grains to ensure diversity. Therefore, when selecting staple foods, it's advisable to choose from a wide range of options.

➁ 算好量

一个成年人每天摄入的主食量约为250克～400克，建议全谷类和杂豆类占50克～150克，薯类50克～100克，同时定期监测体重变化来适当调整食用量。

An adult typically consumes between 250 and 400 grams of staple foods daily. We recommend allocating approximately 50 to 150 grams for whole grains and miscellaneous legumes, and 50 to 100 grams for root vegetables. Additionally, it's advisable to regularly monitor changes in body weight and make necessary adjustments to your dietary intake.

按照每天所需碳水化合物的能量占比计算，一个成年人每餐需要1碗~1.5碗米饭或者1个~2个馒头。

1份50克的生大米约等于半碗米饭（3.3寸碗口，11厘米直径），1份50克的面粉约蒸出中等身材成年女性的拳头大小的馒头。

1份薯类（80克～100克）切块后约为大半碗（3.3寸碗口，11厘米直径）的量。

➂ 善烹调

全谷物和杂粮由于膳食纤维含量较高，口感往往不佳，也可能影响消化吸收。中老年尤其是老年的朋友，咀嚼能力和消化功能会有所减退，这时候一定要注意主食加工的适口性，尽量选择粗粮细做，少食多餐，不要过多摄入粗纤维，防止刺激胃肠道。

Whole grains and miscellaneous grains, due to their high dietary fiber content, may sometimes have an undesirable taste and could potentially impact digestion and absorption. This is particularly important for middle-aged and elderly individuals, as well as seniors, who may experience reduced chewing ability and digestive function. 

During this stage, it's crucial to focus on the palatability of staple foods, choose finely processed whole grains, adopt a habit of smaller, more frequent meals, and avoid excessive intake of rough dietary fiber to prevent irritation to the gastrointestinal tract.

dietary fiber：膳食纤维

digestion and absorption：消化吸收

gastrointestinal tract：消化道、胃肠道

可充分利用现代烹调炊具加以改善。如采用豆浆机、粉碎机进行粗粮细作，制作五谷豆浆或五谷米糊。采用高压锅、电饭煲、电蒸锅等烹调五谷杂粮主食，均可改善口感，提高消化吸收率。

另外，加入芝麻粉、葡萄干和大枣等，可使全谷物食物更美味。

建议：大多数人的粗粮可以占到所有主食的1/2～1/3，老年人可以下降到1/4左右。

编辑：田冉