To Snack or Meal?

They say there was a time last century when we used to eat three meals a day and we should have been thankful for that many because kids were starving in Africa. I suspect they were talking about working adults between 1901 – 1970. I doubt whether kids, teenagers or housewives would have existed on three meals only. If they could sneak a biscuit, leftovers or some bread and dripping they would have gone for it.

Snacking & weight & diabetes

Today, for most readers, food is abundant and affordable and available 24 hours a day. That has led to the question from reader Ken Lynn regarding whether it is better for our weight and health to snack through the day or go back to the three meals a day like grandpa did.

A review by nutrition experts in Australia has looked at the research on snacking and health. There was no clear indication whether snacking had any long-term influence on body weight.

It has been theorised that snacking helps control the appetite and reduce hunger. Nice theory, no evidence. Others have suggested that snacking may cause over-eating, but most studies suggest we compensate to balance the kilojoules in the long-term whether we meal or snack. In other words, we tend to over-eat but snacking doesn’t seem to be the cause.

Snacking doesn’t appear to increase your chances of getting diabetes, nor did it seem to help control blood glucose if you had diabetes.

Snacking & the heart

On the other hand, people who snack and maintain their weight seem to have lower blood lipids (eg blood cholesterol and triglycerides). This link has been known for two decades or more, but we are reminded that these studies haven’t gone for longer than two months, so we don’t know the long-term effects. That’s the consistent problem with human studies of this nature is that they don’t go for long because they are so expensive to run.

Also remember that these types of studies don’t generate profits for a company. For example, if snacking was proven to reduce the chance of a heart attack, it won’t change the nutrition message – if you snack, snack smart on fruit, healthy sandwiches, low-fat, low-salt food bars etc. You see, no quick profit for anyone there because the message is the same.

So what is a snack?

Inherent in many eating research studies is that there is no definition of a snack. That cheese and salad sandwich may be a snack to you, a nibble to an elite athlete, but it might be a meal for grandma. You may recall that I discussed the confusion of snacks vs meals in an earlier blog.

What does it all mean?

I think it is still fair to say that, no matter when or how frequently you eat, your health and weight depends on what you choose to eat. Whether you __meal it__ or __snack it__ will be dictated by how you feel and what suits you. I breakfast, then snack, then finish the day with a meal. Perfect for me, but maybe not for you. In the US they say that snacking will become the norm.

Ken says he is 65 years and wants to crack 85 years. Well Ken, I reckon with a few smart food choices you can make 99 years. It is wise not to make it to 100 because dopey journos have nothing more original than to ask your secret to longevity.

If I ever make it that far my answer would be: “Secret to longevity? Air. Keep alternating an inhalation with an exhalation. Now get lost while I eat my cake.”

Reference: Nutrition & Dietetics 2011; 68: 60-64

GI & Rice

Hi Glenn,

I was wondering if you may be able to help me with a question that a few people have asked me and I am just not sure of the correct answer. I see many young women with polycystic ovarian syndrome who are often pre-diabetic or have diabetes. I encourage my clients and friends to eat a low GI diet and especially when it comes to rice I advise against eating rice such as Jasmine and white rice except for Basmati or Doongara rice.

Last week a friend said to me: "I was raised in an Asian family and our culture has survived just fine for centuries eating this rice and we still do and we are fine even though we eat it a few times every day". He went on to ask me why if they were not obese and didn't have diabetes why we recommend avoiding such rices.

I was wondering if you would mind sharing your thoughts with me on this question. With thanks in anticipation.

Warm regards,

Ginette

Yes Ginette, having asked many folk of Asian background, they much prefer regular white rice rather than brown rice or a low GI rice and have eaten white rice for eons. A traditional white rice based diet also came with vegetables, a little meat, fruit, plenty of activity and a lean body. Under those circumstances they didn't need a low GI rice as the GI of the meal would have been lowered by the vegetables and meat they ate with the rice.

When you add loads of fat, cake, biscuits etc and little activity, very soon you gain weight and it becomes difficult to control blood glucose.

Similarly, there would be little harm in having full cream milk (regarding the fat content), if the rest of your diet was minimally processed, low fat foods. Now, it seems prudent to encourage people to have lower fat milk because they still want a biscuit with their cuppa. It's all about the total diet, more than a single food.

Today we have to give advice about single foods because humans are prone to just eating whatever they like, not what they need. And we find it so much easier to fret about a single food (Diet Coke, dollop of double cream or coffee) than to get a food in the context of a week of eating, or even a single meal.

Coconut Water

As kids we would get whole coconuts from the shop, hammer a hole in two places with a tent peg, pour the water into a glass and drink some before we hammered the coconut to split it open so we could feast on the white flesh. All very exotic in the 1960s.

Now coconut water has gained public interest as a refreshment, especially with the allure of being a natural drink, not a concocted soft drink. Some have even suggested that coconut water has special properties and would make a good sports drink substitute.

Tropical fruit

Coconut water is the water from within the cavity of a coconut, and is not to be confused with coconut milk made from coconut flesh or the coconut oil used in food manufacture. People in tropical countries have enjoyed coconut water for centuries and it is the water of the young coconut that is prized the most, partly because it is sweeter, having a much higher fructose content. Coconuts are grown in about 90 tropical countries.

Potassium and sugars primary nutrients

You can see from the table below that coconut water has a very small amount of protein, virtually no fat, and a modest amount of carbohydrate in the form of sugars. It will quickly empty from the stomach and be absorbed readily by the small intestine. It is low in sodium and a good source of potassium, just like you would find in fruit juice. The sodium content is higher when the water is taken fresh direct from the coconut, around 30-100 mg in 100 mL.

I have compared the information with that of a popular brand in Australia. You can see that Cocobella is sweetened with sugar and pineapple juice because, like when I was a kid, the taste of coconut water wasn’t a winner. Then again, by the time a coconut reached outback South Australia in 1968, it wasn’t likely to be fresh. (Note: Divide kJ by 4.2 to get Cals).

Table. Coconut water per 100 mLs

Is it a health drink? A sports drink?**

Because it is low in sodium it isn’t similar to a sports drink, which has a modest amount of sodium to assist water absorption and retention in sport. Yet coconut water is very well suited as a regular drink with about half the sugar found in soft drinks. One small study indicated that coconut water was a good post-exercise rehydration drink, although it was rated as being less enjoyable than a sports drink. If you are doing plenty of exercise then the sports drink beats coconut water, but if you are looking for a lower kilojoule refreshment compared to soft drinks then a chilled coconut water could be the answer.

What does it all mean?

I suggest that you be really skeptical of any marketing health claims for coconut water. It does have a small amount of minerals and vitamins, but not really enough to get excited from a nutrition standpoint. Enjoy coconut water as a drink and a way to keep well hydrated during mild sweat loss, just note that it is not a substitute for a sports drink in endurance events. I can’t find a true “pure” coconut water in the supermarket around where I live; you may have more luck in the bigger cities or a health food store.

References:

Medicine & Science in Sports & Exercise 2010; 42: 575

Molecules 2009; 14: 5144-5164

Soft drinks & acid

Bronwyn Webb wrote to me and said: "I didn’t realise that diet soft drink was bad for my teeth – I always assumed it was the sugar doing the damage and never thought about the acidity".

It's not just you Bronwyn, virtually everyone thinks that the sugar in the soft drink is what is responsible for any tooth problems. Carbohydrate food particles (eg bread, chips and even apple) that lodge between teeth and remain for some time can be eaten by bacteria in the mouth. While munching on the carbohydrate, the bacteria produce an acid that erodes enamel leading to tooth decay.

Drinks containing sugar don’t stay long enough in the mouth for the sugars to be consumed by bacteria. Excessive fruit juice, energy drinks, soft drinks and sports drinks can all cause enamel erosion through acids such as citric acid. Diet soft drink is as acidic as regular soft drink.

So, don't let those kind of drinks wash around inside the mouth. Drinking through a straw can minimise tooth contact with acidic drinks.

Glucosamine & chondroitin

Come a certain age you begin to take an interest in supplements that aid the memory of car key placement, prevent buttock sag and make joint pain disappear. Glucosamine and chondroitin are meant to help in the latter category, especially regarding osteoarthritis. Both glucosamine and chondroitin are naturally occurring in cartilage and connective tissue in and around joints, so you can see the logic in assuming taking extra as a supplement could help relieve joint pain. Although the argument may be logical, is it physio-logical?

Variation in supplements

There is little agreement about the benefits of glucosamine and chondroitin between researchers, whether for the general public or athletes who give their joints a fair pounding. The consistent problem we have with supplements is that can vary from batch to batch, company to company and they do not have to meet the stringent regulations and proof of efficacy as do medications. Not only aren’t you aware of what you are really getting it also makes it particularly difficult for researchers to both conduct and compare research.

One meta-analysis of six studies involving 1500 people found that there was a delay in the progress of osteoarthritis of the knee after daily use of the supplement for 2-3 years (1). (A meta-analysis is the combination of several studies to get a more precise answer on the effectiveness of a treatment).

Looks good on paper

The authors warn that the results of the meta-analysis should be treated with caution. One reason is because six studies is not enough research on which to base a firm decision. Another reason is that the studies used pharmaceutical, prescription only, products with measured amounts of glucosamine sulphate (1500mg) and condroitin sulphate (800mg). Once other studies with over-the-counter supplements were included in the mix it became very difficult to see either glucosamine or chondroitin having on an influence on joint structure or pain.

Collagen hydrolysate

Be assured that scientists are looking for a natural supplement that will reduce any pain associated with, or the risk of, arthritis as everyone wants to remain mobile throughout life. One such supplement could be collagen hydrolysate. A study of nearly 100 athletes taking 10g of collagen hydrolysate daily for 24 weeks (2) found they experienced much less joint pain. As you know, one study doesn’t provide proof, but it could be one of the new products in the future that extends your knee, hip and athletic lifespan.

What does it all mean?

It’s your call on glucosamine and chondroitin. If you are a believer, continue believing. If you prefer definitive proof (and it may never come) then keep your wallet closed. In the last 12 months there have been three reviews or meta-analysis’ that I know of and they all come to the same conclusion – over-the-counter supplements of glucosamine and chondroitin offer little benefit to your joints (2, 3, 4).

A review by the University of Utah, on glucosamine and chondroitin concluded: “The best current evidence suggests that the effect of these supplements, alone or in combination, on osteoarthritis pain, function and radiographic change is marginal at best. Some patients take these supplements due to a perceived benefit that could represent placebo response, variable absorption, or actual differences in preparations.” (3)

They do acknowledge that there are no safety issues with the supplements, but warn that people taking warfarin (blood thinner) should get approval from their physician before taking either glucosamine or chondroitin.

References:

(1) Rheumatology International 2010; 30: 357-363

(2) Current Medical Research & Opinion 2008; 24: 1485-1496

(3) Rheumatic Disease Clinics North America 2011; 37: 103-118

(4) British Medical Journal 2010 doi: 10.1136/bmj.c4675

Your teeth and acid

Why might a dentist be the first to diagnose the eating disorder bulimia? Because people with bulimia frequently vomit up their meals on the sly and the stomach acid in the mouth begins to erode the tooth enamel, most commonly on the inside of the bottom front teeth. This is very obvious to a dentist taking a squizz in the mouth.

The same effect can be seen with those who drink a lot of soft drink (regular and diet), energy drinks and sports drinks because these drinks have a pH of 2, still acidic enough to erode tooth enamel. Drinking through a straw will help minimise drink-tooth contact. Tingly teeth? See your dentist for an enamel assessment.

Acid food, alkaline food

Should you be eating acid or alkaline foods? Let's see if I can make sense of this. We are oxygen breathing, carbon-based, mildly alkaline life forms. The pH of plasma is 7.35-7.45 and the pH inside our cells is 7.1. If they change much from these levels you will end up in hospital. The body has a number of systems to control the pH in your body (eg lungs and kidneys).

Que? What this thing pH?

Mmmm, I knew this would be tricky from the outset. You may have only heard about pH in shampoo ads. Other readers will remember pH from high school chemistry. The pH is a measure of the hydrogen ions in a solution (ie acidity), that is, the number of hydrogens missing their only electron. A pH of 7 is neutral. The higher the pH the more alkaline. The lower the pH the more acidic. As it is a logarithmic scale, every whole number is a 10-fold difference, so a pH of 5 is 10 times more acidic than a pH of 6. Stomach acid, which is hydrochloric acid, has a pH of about 1. That’s why it burns your throat during regurgitation. Still with me?

Kidneys will sort things out

For a century or so we have known that a high meat/protein diet produces excess acid that must be eliminated from the body via your pee. Foods like meat, chicken, fish, eggs and cheese will generate small amounts of sulphuric and phosphoric acid within the body. If you are a vegetarian then you will likely produce excess alkaline, and this will also exit the body through your pee. This is all quite normal and a happy, healthy body will sort all this out while you get on with life. You will not feel a thing.

Tomato is an acid food, right?

You have probably already deduced that we cannot pick an acid food based on taste. Would you have picked meat as an acid food? It is alkaline on the plate, but will leave an acid residue in the body. Is a tomato an acid food? Nope. Most of the natural acids in tomato will become carbon dioxide and water, leaving a residue of a little potassium bicarbonate, which is, da da da daah, alkaline. Tastes acidic, becomes alkaline. Even when you eat pickled onions, they will land in the hydrochloric acid in your stomach and then trickle into the small intestine where it all the vinegar gets neutralised to a pH of 7 by bicarbonate released from the pancreas.

Acid-base diet does have one major health effect

You will still hear clear-headed health professionals talk about the acid-base balance in your body. Nothing to do with the pH of oranges, tomatoes or lemons or whether they sting your tongue. (By the way, tomatoes don’t cause, or exacerbate, arthritis). As mentioned, eating carcasses of meat each day will generate excess acid which will easily be jettisoned in your pee, but, and here is the problem, along with the acid goes a whole pile of calcium. Eat a very high meat diet for a few years and it will be your bones that suffer. We are happy for you to have that steak sandwich, but please add a whack of salad too as plant foods will help you to keep hold of your calcium stores.

This is also the reason that soft drinks have been linked to poor bone health. Drink a vast amount of soft drink, with an acid pH of 2, and the body will have to rid itself of that extra acid, taking some calcium with it. Of course, when you are quaffing 2-3 litres of soft drink each day (that’s 67-100 ounces of soda) then you are probably not featuring milk in your diet and that compounds the calcium problem.

What does it all mean?

In a healthy body, food does not change the pH of the body, thankfully. Wonderful metabolic processes, evolved over millennia, actively keep the pH of your body within a very fine bandwidth. Forget the “acid” v “alkaline” chat and just eat well, you know, the standard “eat fruit and vegetables, go easy on the cookies, trim the fat off the meat blah, blah, blah” you’ve heard a zillion times. With an emphasis on fruits and vegetables, along with an adequate calcium intake and some sunshine, you will also help your body retain its calcium for bone strength. Just another reason to eat your vegies.

References:

Nutrition Action November 2010

Essentials of Human Nutrition 3rd edition 2007; 110-111