Thursday, October 15, 2009

How much fruit and veg do we eat?

Let’s see if we have got this right – fruit and vegetables are good for you. Why? Well, there are all those wonderful nutrients, all the antioxidants, plus other stuff that seem to protect our brains and eyes, and add the fibre and plant sterols which help our bowels and heart. Of course, they have no added fats, salt or sugars in their natural state. And they are dolphin safe.

Should we be impressed with the list of benefits from fruit and veg? You would think so. But we aren’t. Every group I present to, whether adult or child, have picked up the 2 & 5 message (two fruits and five serves of vegetables in Australia).

Barely 1 in 5 adults get their 2 & 5

Just released is a US report stating that just over a quarter (27%) of American adults eat enough veggies, while about a third (33%) eat enough fruit. Only 14% of their adult citizens are eating both enough fruit and vegetables.

In Australia, a survey of over 1100 adults showed that one in five people (19%) eat enough vegetables and just over half (57%) eat enough fruit. I would just like to remind you that this was a survey, and when you ask humans about stuff, they love to impress the interviewer (ie they tell fibs), so you can bet those figures are an over estimate.

Fruit bonus

Now comes research telling us that we may have under sold fruit from an antioxidant perspective. When polyphenols, a class of antioxidants, have been measured in the past we only picked up a fifth of the total amount. To find the extra a team of scientists from the UK and Spain used an acid extraction process on apples, peaches and nectarines.

“If non-extractable polyphenols are not considered, the levels of beneficial polyphenols such as proanthocyanidins, ellagic acid and catechin and substantially under estimated,” said lead researcher Sara Arranz.

We have no idea what is a serve size

The good folk promoting fruit and veg tell me they have increased intake by about half a serve of each over the last decade, which is commendable. It may be that one barrier we face is that so many don’t even know what a serve size is. Unbelievably, the survey found that only 4 out of 10 people knew that a piece of fruit (apple, pear, banana) was a serve. What was the other 6 out of 10 thinking? Half an apple? One grape? 0.723 of a medium sized fruit? pi x r2 where r= the radius of the fruit? Who knows? More expectedly, only 1 in 8 knew that half a cup of vegetables was a serve.

Should we tell people to eat less fruit and vegetables?

Here’s a common argument: Don’t tell people the really healthy level of exercise they should do because you will scare them and they won’t do any exercise at all. You have to be gentle with humans and get them to exercise for 30 minutes a day, before you tell them they should really be exercising for 60 minutes a day, and even more if they have “trouble with their weight”. Should we tell people to eat 1 & 3, and then gradually encourage them to move to 2 & 5? I prefer to tell people the truth. Exercise for 60+ minutes a day, eat 2 & 5, tea and coffee don’t dehydrate you, diet soft drinks don’t cause cancer, and the best cricketers still come from Australia!

What does it all mean?

Fruits and vegetables aren’t really contributing to health because we just don’t eat enough for them to give us a benefit. Most people don’t know what serve of fruit and vegetables looks like, so maybe we need to make that clear from the outset. With pictures. And then we pass legislation that states that health promotion advertisements need to be simple and fun and not the dictatorial, finger-wagging warnings we seem to get. I have said it many times – when we make fruit and vegetable advertisements like they make beer ads we might have a decent chance of getting men to eat their greens.

References: Public Health Nutrition 2008; 12 (5): 637-643; Journal of Agricultural & Food Chemistry 2009; 57: 7298-7303

Wednesday, October 7, 2009

If you stop exercising, your muscle turns to fat

No it doesn’t. Muscle cannot convert to fat. When you stop exercising then muscles will diminish in size, generally lowering your metabolic rate. The drop in kJs/Calories burned through less exercise and a lower metabolism makes it so much easier to gain kilos as fat. Muscles start to shrink after four decades on the planet, so it is a great idea to keep active through life so that you both maintain your muscle mass and keep your metabolic rate up. That applies to both men and women, especially those that enjoy their chocolate.

Women & chocolate

If you crave for a food, then you are normal, or at least in the majority. Over 80% of young women and 75% of young men feel the need for certain foods, while only two out of three older people have the urge to track down specific foods. Chocolate is the single most craved food. No surprises there.

Women love chocolate. They will do almost anything to acquire it. Men too love chocolate, although pizza is more likely to be their first choice. It is often speculated that the desire for chocolate by women is hormonally driven, with the greatest desire just before, and a couple of days after, the onset of menstruation.

The need for chocolate

Researchers at the University of Pennsylvania recruited 280 women who were either 46, 63 or 82 years old. They had determined that if hormone cycles influenced chocolate desire then there should be a 38% drop in chocolate cravings post-menopausal. However, they found only a 13% drop in cravings. About 90% of pre-menopausal women craved chocolate compared to 76% of post-menopausal women, so it is clear the need for chocolate was profound in most women.

It’s not the hormones

The researchers state that: “the sizeable proportion of women in all age groups who report chocolate and other cravings indicates that the notion of 'craving' is not generation-specific, but rather an experience that is familiar to women of any age.”

Previously, these same researchers had speculated that that this craving could be due to the low levels of progesterone at this time of the month. They gave a dose of progesterone to women who suffered severe premenstrual syndrome (PMS) as part of the treatment for PMS. If the theory was correct, then this treatment should also reduce the cravings for chocolate. There was a slight reduction in the craving for chocolate and other sweet foods, but this occurred in both the treatment group and the placebo group. In other words, the administration of progesterone didn’t seem to be the answer.

What does it all mean?

Most of the prevailing evidence suggests that both men and women like chocolate because the flavour elicits the production of endorphins (natures happy chemicals) in the brain. When people are given endorphin blockers, their desire for, and pleasure from, chocolate is greatly diminished. This research on women supports the view that pleasure is the main driver for chocolate and, maybe, the need for pleasure helps dampen any discomfort from periods. This, in turn, supports the view that chocolate should be tax deductable.

(Note: there is no evidence that your love for chocolate is due to a pharmacological effect or a nutrient deficiency. It’s a pleasure thing.)

Reference: Appetite 2009; 53: 256-259