Choosing the Right Carbohydrates for a Healthy Diet

Author: Yean Toh | Published date: October 26, 2023 | Category: Nutrition

The importance of the right carbohydrates

In recent years, because of concerns over obesity, as well as the popularity of low-carbohydrate diets (such as the Atkins Diet and its variants), carbohydrates have acquired a bad name. Many people seem to have developed a fear of carbohydrates and they try to avoid eating starchy carbohydrates as far as possible.

Understanding Carbohydrate Fears and Misconceptions

This is irrational and dangerous. Starchy carbohydrates are an important source of energy and they form an integral part of a healthy diet. When we avoid starch, we inevitably end up eating more protein and fat. In this short term, this might assist in weight loss. But in the long term, it will lead to other problems. There is no need to avoid starch. Instead, we need to: 

  • Adjust our starch intake to meet our energy needs;
  • Eat the "right" kinds of carbohydrates.

"Right" vs. "Wrong" Carbohydrates: A Matter of Circumstance

What is "right" or "wrong" depends on our circumstances. Normally, we need complex carbohydrates that digest slowly and gradually release glucose into the blood. These are the medium- and low-GI/GL carbohydrates. Most of the time, they are the "right" types of carbohydrates.

Situations Requiring "Wrong" Carbohydrates

The "wrong" types are usually the high GI/GL carbohydrates, including all forms of sugar (refined and raw sugar, honey, etc.), and processed starchy carbohydrates (refined flour products and polished white rice), which release their sugar quickly.
However, there are situations where "wrong" carbohydrates are needed. For example, a person suffering from very low blood glucose is in a medical emergency and the person needs to urgently restore blood glucose levels. In such a situation, a giving a sweet or a sugared drink may save the person's life!

Exploring "Good" Carbohydrate Choices

Here is a brief look at examples of "good" carbohydrates that may be eaten regularly: 

  • Whole grains (Moderate to high GI/GL) are a major source of starchy carbohydrates and fibre. In general, they contain about 70 percent starch. Eat less if you need to control your glucose intake. Examples are brown rice, oats, millet, barley, wholewheat bread and pasta, rye, buckwheat and quinoa. 
  • Legumes (Low Gl/GL) are moderate sources of starchy carbohydrates, containing a mix of carbohydrates, proteins and fats. In general, they contain about 30 percent starch. Examples are beans (soybeans, red/ aduki beans, green/mung beans, kidney beans, navy beans, chickpeas), lentils (red, yellow, dupuy lentils) and fresh legumes (French beans, string beans, green peas, sugar peas and peanuts).
  • Root vegetables (Moderate to high GI/GL) are a major source of starchy carbohydrates. In general, they contain about 30 percent starchy carbohydrates. Eat less if you need to control your glucose intake. Roots that grow downwards tend to be harder, with more fibre and nutrients (especially minerals) and a low GI (except for carrots, which have a high GI). Roots that grow sideways tend to be more porous and starchy, less nutrient-rich and have a higher Gl. 
  • Leaf vegetables (Low GI/GL) contain hardly any starch but a moderate amount of fibre. Among them, cruciferous or "cabbage family" vegetables are highly nutritious, containing important phytochemicals that protect against cancer. Most leaf vegetables should be eaten cooked to destroy anti-nutrients that block nutrient absorption.
  • Fruit vegetables (Low GI/GL) are a minor source of carbohydrates as they contain mainly fibre plus water. Examples include tomato, eggplant or aubergine, bell peppers, chilli, okra or lady's fingers, cucumber, bitter gourd and winter melon. The exception is pumpkin or squash, which is starchy and has a moderate to high GI/GL. It contains about 30 percent starch. 
  • Fruits (Low to high GI/GL) vary greatly in their sugar and starchy carbohydrate content, from very low (in watery fruits), to high (in starchy fruits like banana, dates and sweet tropical fruits like mango and durian). Most fruits have low to moderate GI. But they contain sugar in the form of fructose and sucrose, which can cause other health problems. In general, ripe and sweet fruits have higher GI than unripe fruits that are slightly sour. As sour fruits ripen, their rich content of vitamin C transforms into glucose or fructose. The GL also varies. Since fruits are mostly eaten in small servings, the GL is usually low even in the case of starchy, high-sugar fruits. Most fruits can thus be eaten regularly in small amounts. Dried fruits (moderate to high GL) should be eaten in moderation, especially very sweet dried fruits like prunes, figs and dates. Canned fruits (high GL because of added sugar) should mostly be avoided. Those canned in unsweetened fruit juice (such as some canned pineapple) rather than in syrup are more acceptable.

This content is adapted, with permission, from Book 1 of 2 : The Wonders of Nutrition by Dr Ang Poon Liat. MBBS, M.MED (PAED), MRCP (UK PAED), FAMS, MD.



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