#均衡饮食
#系列课程
什么是碳水化合物？它的作用是什么？
“碳水化合物”是指含糖和/或淀粉的食物的统称。这些食物包括面包、米饭、意大利面、土豆和谷物等。水果和蔬菜也富含碳水化合物，但很少被认为是富含碳水化合物的食物。点击此处了解水果和蔬菜中的碳水化合物。
碳水化合物被人体消化并分解成最小的成分，由称为葡萄糖的单糖组成。葡萄糖具有非常重要的功能，因为它是人体所有细胞的主要能量来源。当你失去控制血糖水平的能力时，就会导致糖尿病。
因此，碳水化合物在饮食中的主要作用是以葡萄糖的形式为身体提供随时可用的能量来源。富含碳水化合物的食物的另一个重要功能是为身体提供重要的营养素。点击此处了解这些营养素。
有哪些富含碳水化合物的食物并不那么健康？
如上所述，富含碳水化合物的食物含有大量的糖和/或淀粉，它们为身体提供葡萄糖作为随时可用的能量来源。这些食物也提供纤维、重要的营养素和抗氧化剂。然而，随着食品加工和制造技术的发展，食品工业极大地改变了我们食用的食物。因此，富含碳水化合物的食物通常经过加工和精制。它们提供糖和/或精制淀粉，但几乎没有重要的纤维和必需营养素。
要了解碳水化合物是如何精制的，不妨以全麦谷物为例。它经过加工制成精制白面粉，因此缺乏全谷物所含的纤维和许多营养素。白面粉随后被用于制造各种不健康的食品，例如白面包、意大利面、饼干和蛋糕。
精制的富含碳水化合物的食物主要提供精制淀粉或糖，而纤维、维生素、矿物质、抗氧化剂和植物化学物质的含量却非常低。因此，这些食物并非健康饮食的最佳选择。这是因为精制碳水化合物会导致血糖水平迅速升高，从而导致氧化应激。
最重要的是，确保你选择的富含碳水化合物的食物包含未精制谷物、水果和蔬菜所含的重要营养素和纤维。
富含碳水化合物的食物中的纤维又如何呢？
富含碳水化合物的食物中含有两种类型的纤维：
粗纤维是指不被胃肠道酶消化的完整植物成分，例如核、种子、硬皮和麸皮。
功能性纤维是指富含碳水化合物的食物中含有的不可消化的碳水化合物。这些不可消化的碳水化合物会被消化道中一种名为微生物群的特殊生物利用。
这两种纤维都对你的健康有益。纤维可以减缓肠道对葡萄糖的吸收，有助于降低血糖峰值，并有助于保持血糖水平更稳定。它还能滋养微生物群，从而促进肠道健康运作并增强免疫力。纤维还能帮助生成重要的营养素，这些营养素可作为强效抗氧化剂。
功能性纤维还能减少肠道对胆固醇的吸收，从而帮助控制血液胆固醇水平，预防冠心病。
富含碳水化合物的食物中，最好的纤维来源包括全谷物和高纤维谷物、高纤维面包和谷物、豆类以及新鲜水果和蔬菜。
哪些类型的食物可以帮助我满足碳水化合物的需求？
富含碳水化合物的最佳食物是那些精制程度较低、能为健康均衡的饮食提供宝贵营养的食物。因此，最理想的选择是所有新鲜水果和蔬菜、豆类以及全谷物和高纤维食物。尽力将这些食物纳入日常生活，是管理健康风险和建立健康生活方式的关键。
本周重点信息
最理想的富含碳水化合物的食物是那些能为饮食提供重要营养素的食物，例如纤维、维生素、矿物质、抗氧化剂和植物化学物质。这些食物包括水果、蔬菜、豆类、全谷物和高纤维食物。
富含碳水化合物的食物是人体的主要能量来源，一旦被人体摄入，就会分解成葡萄糖。葡萄糖会被细胞转化为能量。
精制淀粉类食物和含糖食物与精制程度较低的食物相比，无法提供同等的营养成分，因此被认为不太理想。您应该适量且少量地食用这些食物。
What is a carbohydrate and what is its function?
“Carbohydrate” is a collective term for foods that contain sugars and/or starches. These include bread, rice, pasta, potatoes and cereals, among many others. Other foods that are a source of carbohydrates, but are seldom thought of as carbohydrate-rich foods, are fruits and vegetables. Click here to read about the carbohydrates in fruit and vegetables.
Carbohydrates are digested by the body and broken down into their smallest components, comprising of simple sugars called glucose. Glucose has a very important function as it is the primary source of fuel for all cells in the body. When you lose your ability to control the level of glucose in your blood, the result is diabetes.
The primary role of carbohydrates in the diet is therefore to provide the body with a readily available source of fuel in the form of glucose. The next important function of carbohydrate-rich foods is to provide important nutrients to the body. Click here to read about these nutrients.
Are there carbohydrate-rich foods that are not so healthy?
As mentioned, carbohydrate-rich foods contain a large percentage of sugars and/or starches, which provide the body with glucose as a readily available source of energy. These foods also provide fibre, important nutrients and antioxidants. However, with the development of food processing and manufacturing, technology has allowed the food industry to change the foods we eat significantly. As a result carbohydrate-rich foods are often processed and refined. They provide you with sugar and/ or refined starch, but with very little in the way of important fibre and essential nutrients.
To understand how carbohydrates can be refined, consider whole-wheat grain. It is processed through manufacturing to refined white flour, and consequently lacks the fibre and many nutrients that whole grains possess. White flour is then used to manufacture a multitude of unhealthy food products, such as white bread, pasta, cookies and cakes.
Refined carbohydrate-rich foods provide mostly refined starch or sugar and have very little to offer in terms of fibre, vitamins, minerals, antioxidants and phytochemicals. Therefore these foods are not the best choice for healthy eating. This is because refined carbohydrates cause the blood glucose levels to rise rapidly, contributing to oxidative stress .
The bottom line is to make sure your carbohydrate-rich food selection contains the important nutrients and fibre that unrefined grains, fruits and vegetables have.
What about fibre in carbohydrate-rich foods?
There are two types of fibre found in carbohydrate-rich foods:
Roughage refers to intact plant components that are not digested by gastrointestinal enzymes, for example pits, seeds, tough skins and bran husks.
Functional fibre refers to non-digestible carbohydrates found in carbohydrate-rich foods. These non-digestible carbohydrates are used by special organisms called microflora that reside in the digestive tract.
Both forms of fibre are beneficial to your health. Fibre slows the absorption of glucose from the gut, helping to reduce glucose spikes, and contributing to more stable blood glucose levels. It feeds the microflora, which help to promote the healthy functioning of the gut and better immunity. Fibre also plays a role in producing important nutrients which can be used as potent antioxidants.
Functional fibre is also associated with reduced cholesterol absorption in the gut, which in turn helps manage your blood cholesterol levels and prevents coronary heart disease.
The best sources of fibre in the carbohydrate-rich food group include whole grain and high fibre cereals, high fibre breads and grains, legumes and fresh fruits and vegetables.
What types of foods will help me meet my carbohydrate requirements?
The best types of carbohydrate-rich foods are those that are less refined and contribute valuable nutrients to a healthy balanced diet. The most desirable choices are therefore all fresh fruits and vegetables, legumes and whole grain and high fibre foods. Doing your best to incorporate these into your daily routine is a crucial part of managing your health risk and engaging in a healthy lifestyle.
Key messages for this week
The most desirable carbohydrate-rich foods are those that contribute important nutrients to the diet, such as fibre, vitamins, minerals, antioxidants and phytochemicals. These are fruits and vegetables, legumes and whole-grain and high-fibre foods.
Carbohydrate-rich foods are a primary source of fuel for the body, and once eaten, are broken down to form glucose. Glucose is used by your cells for energy.
Refined starchy foods and sugary foods do not contribute equivalent amounts of nutrients to the diet compared to less refined forms, and as a result are considered to be less desirable. You should eat these foods in moderation and infrequently.
