Here is where I share my thoughts, ideas and opinions about the world of nutrition, food and health. I hope you find good sense, helpful guidance and inspiration to eat great healthy food that makes you feel good.

I write regularly for GI News, an online newsletter for 60,000+ Australasian and International subscribers interested in the glycemic index (GI) and associated health topics such as diabetes, weight loss and a healthy heart. It’s a great read.


11 May 2015

Is raw food best?

Posted by 2142 2142 on Monday, May 11, 2015

Nothing beats the crunch of a raw carrot or the crispness of lettuce and cucumber in a salad. However, you can take a good idea to extremes. There is a whole diet tribe who only eat raw foods, believing it to be best for weight loss, health, wellbeing, longevity and prevention of disease. It’s kind of like the advanced, super duper version of the vegan diet. Raw foodists are responsible for the rise of raw cacao (discussed last time), cold-pressed virgin coconut oil, green smoothies, protein balls and cauliflower pizza bases (!). Raw food diet followers exist on raw vegetables, fruits, nuts, seeds, sprouted beans and seaweed – none of which can be heated above 37.8°C (116°F), about body temperature – or else they believe enzymes will be destroyed and the food won’t be as well digested and absorbed. This is a load of rubbish. The enzymes are for the plants’ benefit, not ours. Enzymes are very small proteins and are almost instantly denatured during digestion like any other protein in our food.

The idea that plant foods should be eaten raw to extract their nutrition is just false. In fact, so called ‘anti-nutrient’ factors in raw plant foods make them harder to digest. Phytates can reduce absorption of minerals such as iron and zinc, and nuts contain enzyme inhibitors in the skin. Of course, the level of some vitamins (such as vitamin C) and antioxidants (sulforaphane) are reduced by the cooking process; however, in a mixed diet this is not an issue (still, don’t boil the life out of your vegetables but lightly steam, microwave, stir-fry or roast them instead). I know a whole bunch of raw foodists will be horrified at my mention of the microwave, which many natural health proponents say will kill you slowly. That's also rubbish; that is to say there is no evidence to back this up.

Processing vegetables by juicing, mashing, pureeing or cooking actually releases more vitamins and antioxidants from vegetables than eating them raw and whole. For example, more lycopene (an antioxidant) is absorbed from a tomato pasta sauce than raw tomatoes, and the same goes for beta-carotene from carrots. The physical effects, as well as higher temperature, soften and break the tough cell walls in plant foods so their inner goodies can be released. In fact, an Italian study comparing steaming, boiling and frying found all methods increased the availability of antioxidants in zucchini (courgettes), carrots and broccoli. The availability of cancer-fighting indoles in cruciferous vegetables such as cabbage is also higher after cooking.

Because it is very bulky, high in fibre and nutrient-sparse, a raw food diet carries a very high risk for people with higher nutritional needs, such as children and pregnant women—they need a lot of nutrients the body can easily get at. If you have sensitive bowels, such as Irritable Bowel Syndrome, this diet will only lead to tears (from pain in your gut) because of its very high fibre content. And the taste? I’ll leave that for you to decide, but I contend this is an extreme diet you do out of conviction rather than enjoyment. And looking on raw food diet websites, their recipes seem to be heavy on sweet treats such as raw chocolate cheesecake, puddings and biscuits, perhaps because this diet is desperate to convince us it's not all jaw-fatigue and rumbling bowels, but it can be some fun too. 

But like all fad diets. this one is really about belonging to a tribe. Being ultra-choosy about the food you eat and going to a lot of trouble to prepare it is a folly of the wealthy and well-fed and a by-product of a culture in which fashion and celebrity trump science and common sense. Luckily, the raw food tribe is typically young and appearance-conscious and will let it go in time - it's just too much hard work and incompatible with family life.

Long story short Besides being a heck of a lot of trouble, you do not need to follow a raw food diet to be healthy. Enjoy a balanced diet from all the food groups and a variety of raw and cooked foods.

Hungry for more? Read Richard Wrangham’s book, Catching Fire: How Cooking Made Us Human. Its a fascinating exploration into the origins and physiological imperatives of cooking.

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