By Zhang Yu-fan
Abridged and translated by Wu Hsiao-ting
Hualien Tzu Chi Hospital and Tzu Chi volunteers in Hualien, eastern Taiwan, launched the Healthier Me 21-Day Challenge in August 2021, inviting members of the public to try a whole-food, plant-based diet. This diet avoids the intake of meat, eggs, and milk. But can such a diet be nutritionally balanced? Dr. Zhang Huai-ren of the Department of Cardiology at Hualien Tzu Chi Hospital and Dietician Su Zhen-ying weigh in on this and other important questions.
Dr. Chang Huai-ren of the Department of Cardiology at Hualien Tzu Chi Hospital suggested that people interested in a whole-plant diet try the 21-day health challenge before deciding whether to turn the diet into a long-term habit. Courtesy of Hualien Tzu Chi Hospital
Q: Is the whole-food, plant-based diet promoted by the health challenge program too strict and therefore difficult to maintain?
A: Instead of focusing on how long the diet lasts, one’s focus should be on establishing good dietary habits that can last beyond the 21-day challenge.
The Healthier Me 21-Day Challenge originated from an online health promotion program launched in 2009 by America’s Physicians Committee for Responsible Medicine (PCRM). Participants of the PCRM program had to eat according to a Power Plate created by the committee. The Power Plate consisted of four food groups: fruit, vegetables, legumes, and whole grains, each making up a quarter of a meal.
Dr. Chang Huai-ren (張懷仁) of the Department of Cardiology at Hualien Tzu Chi Hospital pointed out that many healthy dietary programs emphasize caloric intake, but the focus of the Healthier Me 21-Day Challenge is on a whole-food, plant-based diet—it doesn’t fixate on counting calories. The diet itself happens to be high in fiber and low in calories, so counting calories isn’t necessary. As long as a participant doesn’t feel hungry from such a diet and makes sure that the four food groups each make up a quarter of their meals, the calories will take care of themselves. (It should be noted that the amount of vegetables is allowed to surpass that of the fruit in the challenge.)
This whole-plant diet stresses the use of little oil, salt, and sugar. Food preparation methods that involve large amounts of oil, salt, and sugar, such as gratinéing, deep-frying, frying, and pickling, are to be avoided. Steaming, poaching, stewing, and roasting are the preferred cooking methods in the program.
Dietician Su Zhen-ying (蘇真瑩) explained that participants are not allowed to eat more than a tablespoon of oil per meal during the 21 days of the health challenge program, and that salt is limited to no more than six grams a day. Sugary beverages should be avoided and replaced with plenty of water. In fact, it’s recommended to consume at least 30 milliliters of water for every kilogram of weight. A person weighing 60 kilograms (132 pounds), for instance, needs at least 1.8 liters of water per day. If participants crave a beverage, they should opt for black coffee or tea without added sugar. Fruit juices are discouraged.
Why is every round of challenge set at 21 days? According to Dr. Chang, 21 days is the shortest amount of time to see any obvious changes in one’s health numbers. It’s also the minimal time required to create a new habit. It might be difficult or impossible to make a full switch to a whole-plant diet, so taking part in a program like the 21-day challenge is a good way for participants to decide whether a whole-plant lifestyle suits them or not.
To help participants better track the changes in themselves, their height, weight, and blood pressure are measured before and at the end of the 21-day round for comparison. Blood tests are also taken to see if there are any changes in their blood sugar and blood fat levels.
Q: What are the differences between a whole-plant diet and a conventional vegetarian diet?
A: A whole-food, plant-based diet consists primarily of natural and unrefined foods. Only minimally processed ingredients are allowed.
A whole-plant diet focuses primarily on eating whole foods: things that are as close to their natural state as possible. For example, whole fruit is recommended over fruit juice, sweet potatoes instead of sweet potato cake, and whole potatoes over French fries or hash browns. The fewer additives or chemicals a food contains, the better.
Though heavily processed foods with a high oil, salt, or sugar content are to be avoided, processed foods are not completely banned in the diet. It’s just that such food shouldn’t be so overly refined or processed that its nutrients and fibers are lost in the process. Based on this principle, brown rice, foxtail millet, quinoa, and oatmeal are recommended over refined rice or noodles.
Dietician Su pointed out that one hundred percent whole-wheat noodles or breads are allowed in the whole-plant diet because they are minimally processed and have all the nutrients present in the original whole food. Therefore, when choosing whole-grain food for their meals, partakers of the whole-plant diet are free to opt for brown rice noodles, whole-wheat pasta, whole-wheat bread, and whole-grain baguettes made from flour free of oil.
Dr. Chang added that when deciding on what food is permissible on a whole-plant diet, a key factor for consideration is how the food in question has been processed. Many foods cannot be eaten unless they are processed in some way, but even after being processed they still retain the nutrients in the original food. Examples include soybean milk, tofu, nattō, low-salt miso, tempeh (an Indonesian food made from fermented soybeans), and uncolored or unbleached dried tofu.
Soybeans are one of the most important sources of protein in a whole-plant diet. According to Dietician Su, soybeans contain all eight essential amino acids, unlike other plant proteins, which usually lack at least one essential amino acid. The protein content of soybeans is comparable to that of meat-based protein.
However, raw soybeans contain trypsin inhibitors that interfere with protein digestion. As a result, soybeans can trigger flatulence or indigestion if eaten raw. Heat treatment during processing serves to inactivate the trypsin inhibitors. Consuming soybean products such as soybean milk, tofu pudding, or tofu can help prevent indigestion caused by eating raw soybeans.
Dietician Su Zhen-ying of Hualien Tzu Chi Hospital pointed out that a whole-food, plant-based diet, if properly planned and executed, can satisfy the health needs of people of all ages. Hsiao Yiu-hwa
Q: Since a whole-plant diet does not contain fish, meat, eggs, or dairy, is it nutritionally insufficient?
A: A whole-plant diet produces adequate nutrition for the human body, but it’s recommended to supplement the diet with plant-based omega-3 fatty acids and vitamin B12.
Dietician Su said that to judge whether a diet is nutritionally balanced, one needs to look at the overall proportions of the six major nutrients in the diet. The six essential nutrients that the body needs to function properly include carbohydrates, protein, fats, vitamins, minerals, and water. They are the building blocks for growth and repair and substances essential to regulate chemical processes in the body.
The dietician stressed that even though a whole-plant diet contains no dairy or meat, it can still meet the body’s nutritional requirements. Both the Academy of Nutrition and Dietetics in the United States and the British Dietetic Association have pointed out that a properly planned and executed whole-plant diet can satisfy the health needs of people of all ages.
Even so, Dr. Chang reminded people on a whole-plant diet to pay attention to their intake of omega-3, a polyunsaturated fatty acid. Omega-3 fatty acids have anti-inflammatory properties. They can reduce triglyceride levels in the blood and are good for the heart and blood vessels. Since the human body cannot make these fatty acids on its own, they must be obtained from diet.
One of the main sources of omega-3 is fish oil, but fish isn’t the only food that provides omega-3. Other good sources of omega-3 fats include oils made from walnuts, flaxseeds, chia seeds, and rapeseeds. Just one tablespoon of flaxseed oil, for example, can meet an adult’s daily need for omega-3.
Since a whole-plant diet encourages the ingestion of only a small amount of oil, Dr. Chang suggested that people on such a diet eat a tablespoon of flaxseed powder every day. Dr. Chang himself does this every day. “You can ground flaxseeds into powder and add it to your food or drink,” the doctor said. “You can also eat the powder directly with water.” Eating powder instead of oil has another benefit: it prevents you from ingesting the additives used in the oil production process.
People on a whole-plant diet are also advised to pay attention to their Vitamin B12 intake. Vitamin B12 is an important nutrient that helps make red blood cells and DNA, the genetic material in all cells. Though gut bacteria in the large intestine of humans can make B12, humans cannot absorb it there. The absorption of most nutrients occurs in the small intestines, upstream from the large intestines. Vegetables and fruit do not contain B12, which is why vegetarians are recommended to take B12 supplements.
That being said, vitamin B12 deficiency isn’t just an issue for people who eat only plant-based foods; meat eaters may face the same problem too.
Dr. Chang explained that vitamin B12 from food must be bound to intrinsic factor, a protein secreted by cells in the stomach, for normal absorption. Since intrinsic factor is made in the stomach, conditions affecting the normal workings of the stomach can interfere with the availability of intrinsic factor. People with gastric ulcers, those taking antacids, or those who have had a gastrectomy are therefore advised to take B12 supplements.
America’s National Academy of Medicine (formerly called the Institute of Medicine), on the other hand, recommends that everyone aged 50 or above, vegetarian or not, should take B12 supplements.
