Eat like a cave man

What is the perfect diet? If you go by what you read in the media, you might toss up between the Mediterranean diet, the low-carb diet, or the Japanese diet. Now and again you will hear of the hunter-gatherer diet, or cave man diet, touted as the ideal choice as it was the diet for most of human ancestry.

The hunter-gatherer diet should probably be termed the gatherer-hunter diet as our forebears did more gathering than hunting. Either way, from here on I shall call it the Paleolithic diet. This is the diet we enjoyed before humans started to cultivate plants, domesticate animals and consume dairy foods about 10,000 years ago.

No bread, milk or baked beans for most of evolution

So, for two million years humans and their ancestors dined on wild animals, fruits, vegetables, nuts and seeds (but not legumes). There were no oils, dairy or grain-based foods in this time. This may be the ideal diet as our physiology evolved to make best use of these foods. Ten thousand years is a relatively short time to adapt to the dramatic changes we have experienced in our diet. Certainly, no-one would suggest that the body was designed to eat Krispy Kreme donuts.

Paleolithic diet improves metabolism

A University of California study was designed to see the effect the Paleolithic Diet on human physiology when compared to the modern diet. Due to the time and commitment required only nine healthy people completed the 17 day trial in which the last 10 days was exclusively the Paleolithic diet. During that time their blood cholesterol dropped by 16%, triglycerides by 35% and a significant drop in blood pressure even though none had high blood pressure in the first place. Blood glucose and insulin levels also improved. There was no weight loss or change in exercise patterns in the group, so any metabolic effects observed were due to the change in diet.

As Professor Loren Cordain, a big fan of the Paleolithic Diet said: "Our genome is very well adapted to wild plant and animal foods, and these giant come-latelys (grains, dairy, legumes) have potential effects of being discordant with our genome”. This small study suggests at least a short-term benefit to trying the diet.

“So what are the recommendations? Reduce processed foods, and increase fresh fruits, vegetables, nuts, lean meats and seafood” Cordain concluded. Makes sense all round. There are many adherents to the diet. For more information on the Paleolithic Diet go to http://www.paleodiet.com.

What does it all mean?

I think the debate on the ideal diet is all a bit theoretical. Even if the Paleolithic Diet is the best diet for humans, I don’t think I could live the rest of my life without camembert cheese, red wine and chocolate. I prefer the Comidas del Mundo Diet, which is one I just made up. It doesn’t have a web page yet, but should it become fashionable, then you will know where it began. Basically, you choose good quality food and dishes that originated from around the world and enjoy them, such as tomatoes (origin South America), tea (China), yogurt (Persia), chocolate (Switzerland via South America), macadamias (Australia), and combine that with activities that exercise the brain and body. I might call the combination La Vida Ecléctica Health and Anti-Aging Program. But, then again, I probably won’t. I don’t really like to be programmed.

Reference: European Journal of Clinical Nutrition 2009; 90: 269-275

Biting less than you can chew

“Don’t put so much in your mouth” is the advice parents give at the dinner table, especially to teenagers just arrived home after sports training. I used to eat at the same table as a motorbike fanatic at boarding college in Adelaide. We used to call him “hoovermouth” as he would fill his mouth until he had cheeks like a trumpet player. He would also eat with oily hands because his theory was that bacteria couldn’t live in oil.

It appears that how much you stick in your mouth could influence how much you keep sticking in your mouth. One weight loss tip has always been to take small bites, chew your food and put your knife and fork down between mouthfuls (assuming you haven’t got your mitts around a burger or dipping your fingers into a bucket of popcorn).

Custard experiment

Now Dutch researchers have added a touch of credibility to that advice. Twenty two healthy, young people, without eating disorders or strange boarding house table habits were selected for the experiment. And they had to like chocolate custard too.

The custard was provided in controlled amounts – small bite size, large bite size and bite size of choice – while also being in the mouth for set amounts of time – three seconds, nine seconds or a time they preferred. The time in the mouth was termed the Oral Processing Time, or OPT, as scientists love acronyms. Every thing was automated. Little beeps would signal when to bite and when to swallow. They were told to stop eating when they felt comfortably full.

Less food, more time

The least total amount of custard was eaten when the bite size was the smallest and the OPT was the longest. Compared to eating the custard ad libitum, they ate 32% less food before feeling full. Once either the bite size was increased or the OPT was shortened, more total food was consumed.

Although the eating situation was highly controlled and therefore not natural, the results were supportive of previous similar research. One earlier study even had people wear a dental prosthetic to reduce the oral cavity in the mouth and found they ate 25% less food. Why hasn’t someone put those on the market yet?

What does it all mean?

It makes sense that if we take longer to eat our meal, the hormones that trigger the appetite centre are going to kick in before we overeat. It also makes sense that we should take a little longer to enjoy the flavour and texture of food (aka chewing).

The advice to bite off smaller amounts and enjoy them over a longer time has always been good advice it seems. There lies one of the problems we have with many take-away foods – their flavour hits the palate quickly in the form of fat, sugar and salt and they are usually soft and quick to eat, chewing hardly required.

Reference: American Journal of Clinical Nutrition 2009; 90: 269-275

Does chocolate give you zits?

Well, your Mum always reckoned it did when you were a teenager. That’s only because she loved you and thought it was helpful advice, not because she had read all the science on the topic. But, then again, there wasn’t much science on the link between food and acne anyway.

A lot of the research conducted last century wasn’t really high quality and led to the scientific view that what you ate probably didn’t make any difference to pimple production. A 1997 review article in the New England Journal of Medicine on the treatment of acne states: “Physicians should dispel the myth that diet or failure to cleanse the skin is responsible for acne.”

Case closed. And then reopened

When subscriber Mel asked if there was a link between chocolate and pimples, the answer would have been easy last century: No, Mel, there isn’t. The research on chocolate and other foods had shown no link between it and pimples. The case was closed. Then the case had to be re-opened again as a new theory emerged. Before I tell you about that, first what is acne?

What is acne?

Acne is an abnormality within the sebaceous glands associated with hair follicles on the face, back and chest. The whole process of acne begins at the age of 7-10 years, when hormonal surges cause the sebaceous glands to enlarge. Acne usually becomes visible in puberty, initiated by an increase in androgen hormones, especially dehydroepiandrosterone sulphate (DHEAS). The sebaceous glands secrete sebum that naturally flows to the surface of the skin. Should this flow be blocked by a plug (called a comedo), the oily sebum accumulates, and bacteria (Propionibacterium acnes) feed on the fats in the sebum and accumulate to eventually reach levels that form a pimple. (OK, close your eyes and repeat that back to me).

Not one food, but the diet as a whole

In 2002, a theory was proposed that, as non-westernised societies have almost no acne, a diet of high Glycaemic Index (GI) foods might influence the formation of pimples. Those carbohydrate foods that are quickly digested (ie high GI foods) may trigger high levels of insulin in the blood, elevating Insulin-like Growth Factor 1 (IGF-1), which in turn stimulates sebum production.

Subsequent published research tends to give this theory some credibility. A pilot study at the Royal Melbourne Institute of Technology, Australia on a small group of male teenagers confirmed that a high GI diet influenced hormones to promote acne development. This is still only a theory and more research needs to be done before any conclusions on GI and acne can be made.

As chocolate has a low to moderate GI (and has a moderate insulin response), this theory may not be relevant to chocolate consumption anyway. So, the answer to the original question remains: No, Mel, there isn’t.

What does it all mean?

Although we have a lot more to learn about pimples and diet, it seems safe to say that no single food causes acne; it is more likely to be the effect of the overall diet. As a general rule of thumb, the better the quality of the diet, the lower the GI and the less likelihood of getting a zit. Choosing highly processed foods tends to lead to higher blood glucose levels, higher insulin, changes in hormonal levels and a greater chance of waking up with a huge zit in the middle of your forehead.

Reference: Mol Nutr & Food Research 2008; 52 (6): 718-726

Chocolate after a heart attack

Chocolate is a much studied food. Now there is yet another research paper suggesting that it is never too late for chocolate. It has been long known that the cocoa in chocolate has antioxidants that seem to promote healthy arteries, lower blood pressure, reduce blood clots (eg deep vein thrombosis) and stop LDL-cholesterol from being oxidized into a dangerous form. All good news if you are otherwise healthy and eat only sensible amounts of choc.

But what if you have already had a heart attack and been lucky enough to survive it? A study of 1169 people who had a heart attack in the 1990s found that chocolate eaters had a 27% reduced chance of another attack when compared to those never eating chocolate. Although an occasional nibble conferred some protection, those that ate chocolate at least twice a week had the best outcome. The patients were not asked if the chocolate was milk or dark.

This was an observational study and we must be careful not to conclude that chocolate was the answer. On the other hand, sometimes it is nice to jump to conclusions on certain food experiences.

Reference: Journal of Internal Medicine 2009; 266: 248-257

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

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