Food + Beverage
Contrary to popular belief, stir-frying vegetables is NOT a healthy way of preparing them. According to research at the Chinese University of Hong Kong, it is, in fact, one of the unhealthiest cooking methods there are. So how should vegetables be prepared?
It’s always disappointing to discover – later in life – that one of your cherished beliefs was wrong and that your mother was right all along. Boiling vegetables really IS one of the healthiest ways of cooking them.
When it comes to cooking vegetables, my mother – like most American women of her generation – boiled them. I believe girls were taught to do this in junior high home economics classes, while we boys were studying wood shop in another part of the campus.
It didn’t matter if they were broccoli or peas and carrots or spinach – vegetables (when I was growing up) were almost always boiled.
By the time I was coming of age, Northern California was undergoing a culinary revolution, which was affected in no small measure by immigration from Latin America and Asia.
Along with the new immigrants came new ingredients and new ways of cooking.
Suddenly it became old school to boil vegetables and serve them topped with butter and gravy. Stir-frying – that exotic technique from Southern China – became the accepted way to cook vegetables
Not only did vegetables taste better when they were stir-fried, but they were also healthier. Or so we were told …
Chinese Cooking Class
It was in the late 1970s that I enrolled in a Chinese cooking class at the Chinatown YMCA in San Francisco.
That’s where I learned the fine art of stir-frying, which isn’t really all that difficult. It all gets down to “timing”, as our teacher reminded us time and time again.
And, of course, preparation: everything had to be carefully prepared in advance so that when you started to cook, you could quickly throw the ingredients into the wok, and quickly stir-fry them.
Overcooking was the death of Chinese (or should I say Cantonese?) cuisine.
My teacher basically divided ingredients into two categories: meat (including poultry or fish) and vegetables.
First, the meat should be cooked and removed from the wok. Then the vegetables should be cooked.
Then the meat should be returned to the wok along with the sauce soy and any other ingredients, which were usually liquid or powder.
The heat should be turned down, the wok should be covered, and the meat, vegetables, and other ingredients should be simmered together at a low heat.
Each step, she said, should take about two minutes (six minutes in total).
Scoffing at Tradition
As a Chinese American, my teacher was a bit irreverent – scoffing, sometimes, at tradition. She said that while the meat should be cooked in oil, the vegetables should be cooked in butter.
“Chinese people will tell you that butter isn’t Chinese so you shouldn’t use it when you cook Chinese food, but vegetables taste better cooked in butter,” she said.
“The only reason Chinese people didn’t cook with butter is because they didn’t have it. If they had had it, they would have cooked with it.”
The teacher said the same thing about wine.
“All good chefs cook with wine, and so should you,” she said.
“Wine enhances the flavour of everything. Don’t let anyone tell you not to use it because ‘it isn’t Chinese’.”
The teacher also suggested adding a bit of sugar along with the soy sauce and the wine, something else, she warned, that might arouse criticism. Whatever …
After taking this very enjoyable class, stir-frying became my standard method of cooking vegetables. Even if I was cooking steak, I would always prepare vegetables the Chinese way.
The Health Factor
A few years ago, I read in the South Chinese Morning Post (an influential English language newspaper in Hong Kong) that research done at the Chinese University of Hong Kong (CUHK) had revealed that stir-frying vegetables in oil was extremely unhealthy.
Apparently, oil, vegetables, and high heat were a lethal combination that produced carcinogens. Whereas it was okay to cook meat in hot oil, it was NOT okay to cook vegetables in hot oil.
This had nothing to do with heart disease – that’s another issue altogether. It was the chemical reaction that took place when vegetables were fried in oil at a high heat.
The researcher interviewed in the story recommended using “healthier cooking methods” such as steaming or – you guessed it! – boiling.
Does that mean my mother was right?
I couldn’t help but wonder if health – in addition to taste – was why my Chinese cooking teacher in San Francisco had recommended using butter rather than oil.
Cooking classes, after all, were only a hobby for her. Her real profession was dietitian. She worked at a hospital. Could nutrition have been a factor?
Or maybe not … Maybe it was just about taste … I took these classes a couple of decades before the research I’m referring to was done.
Last summer, I had the opportunity to interview a professor of nutrition from an Italian university on the health benefits of the Mediterranean diet, an area in which she had done extensive research.
Why was the traditional Mediterranean diet healthier than the traditional American or the traditional Finnish diet?
To dumb things down, it got down to two basic factors: the ingredients and the way they were cooked.
After I had obtained the information I needed to write the article I had been commissioned to write, we continued to chat. I told her about the research that had been done at CUHK, and asked her opinion.
She agreed that vegetables should never be stir-fried in oil. But when I asked her about frying them in butter, she said, “That’s even worse!”
When I suggested frying them in margarine, she said, “That’s even MORE worse!”
The professor concurred with the CUHK research that vegetables should either be boiled or steamed – unless, of course, you were going to eat them raw.
But she was quick to add that not ALL vegetables should be consumed raw. Some vegetables – such as broccoli – should always be cooked, and that meant boiling or steaming them.
The Secret Ingredient
But what about taste? I could never understand why broccoli tasted so good when it was cooked by Cantonese chefs.
There didn’t have to be any fancy sauces. Usually, it appeared to be boiled. But it tasted so much better – even without gravy or butter – than it did the way Americans traditionally cooked it.
I had tried this, that, and the other thing until I finally stumbled across their secret. It came to me in a flash one evening as I was about to throw some broccoli into a pot of boiling water.
“What would happen if I threw in a dash of chicken powder?” I wondered.
OMG! That was their secret! Rather than boiling broccoli in plain water, Cantonese chefs boiled it in chicken stock!
(I had long before figured out that they didn’t stir-fry broccoli. I had tried that many times, and the results were always a disaster.)
I also came across the chicken powder trick in some Western recipes a short while later.
Even some beef dishes called for either chicken stock or chicken powder. I was surprised at first – until I remembered the impact that chicken powder had on cooking broccoli.
In terms of adding a bit of sugar to recipes, I started experimenting with honey as a tastier – and healthier – substitute years back.
I came across this idea while dining in Taipei several years ago. There was a subtle nuance in some of the dishes at a particular restaurant that I ate at twice, and I came to the conclusion that they must have used honey rather than sugar in the preparation of their dishes.
Stir-frying with Water
Now that I’ve learned that you should never stir-fry vegetables in oil, butter, or margarine, I’ve discovered that simple water works every bit as well – but is a bit more labour intensive.
I start by heating the pan (or the wok) and then adding some water until it starts to sizzle.
(It’s important to keep additional water nearby because it evaporates MUCH more quickly than oil and needs to be topped up frequently.)
First, I stir-fry the meat (in half the pan) and some onions, garlic, ginger, and minced red peppers (in the other half of the pan) until the meat and other ingredients are cooked. I don’t bother removing the meat as my cooking instructor had instructed.
Then I add the vegetables and stir-fry them together with the meat for about two minutes (or until they look ready – some veggies take longer than others).
I add a splash of red or white wine.
Then I add a pre-mixed combination of roughly equal parts of honey (I prefer Ginseng & Honey by El Briezal of Spain), chicken stock (or in my case, Knorr’s Chicken Powder), low sodium soy sauce, corn starch, and water (make sure to stir well before adding).
I stir the sauce well into the meat and vegetables, turn down the heat, cover, and let it simmer for about two minutes.
All I can say is, it tastes great. And it looks great, too, because the honey thickens the gravy and adds a shiny finish (many Chinese chefs use oil for this purpose).
My only question is, is cooking vegetables in a small about of water and/or chicken stock healthier than frying them in oil (or butter or margarine)?
That I don’t know. But if I ever get another chance to interview a professor of nutrition, that will be one of the first questions I ask!