We don't only eat according to knowledge. The foods that we choose are dependent on a wide variety of factors. So some of that might include cost. Other things that influence what we eat might be time. So a lot of people, they work long hours, they've got kids to look after, they're running around. So having that time to prepare healthy foods can sometimes be difficult for people. And, you know, they end up just taking the easier option, which is grabbing some takeaway on the way home, or some convenience foods. And sometimes they can be healthy, but a lot of the times they're not. Culture influences what we eat. Festivities, birthdays, Christmas-- there's all different influences, apart from just knowledge, that determine what people choose to eat every day.
It is still possible to eat healthfully, regardless of all those parameters and influences. What we do need to know is how to work within that. So, for example, how to cook healthfully on a budget. Or how to prepare healthy foods when you don't have much time. Examples of that might be knowing what sort of takeaway foods to choose. Or cooking foods in bulk and putting some in the freezer, when you do have a little bit more time. And easy recipes. There are some recipes that are really healthy that you can prepare in just 10 minutes.
Restaurant foods are often higher in fat and higher in salt, and research is showing that the portion sizes served in restaurants is bigger than what most people would serve at home. So being careful about what restaurants you go to, what sorts of foods you choose from the menu. Keeping in mind those larger serving sizes, perhaps you can share three dishes amongst five people, for example, to make sure that you're not eating more than what you actually need to.
There is a lot of nutrition information out there, and there are a lot of diets out there. And, unfortunately, those diets are usually quite fixed, and they won't fit in to every individual's lifestyle. So don't feel bad if you can't follow the guidelines exactly. But making small steps to go towards those targets is really beneficial. So I've had clients come to see me because they've wanted to improve their diet, or lose weight, or whatever. And I've started talking to them about what sort of foods they should choose, and they just say, Simone, just give me a plan an I'll follow it. But unfortunately, that never seems to work. They can follow it for a few days, but then it's more restrictive, because it doesn't fit in with their budget, or their taste, or their lifestyle. And then they just go back to the way that they were eating before. So, yeah, it's really important to understand why we eat, and why you, personally, eat the way that you eat. So therefore, you can find a way to eat healthfully and apply all of that knowledge that fits in with your lifestyle and tastes.
What we eat is way beyond just what we know we should eat.
Popular diets
We must remember that while nutrition is a science, the way we eat can be considered a behaviour.
Even though we are learning more than ever about nutrition and how it can affect our health, knowledge alone is not the only driver behind our food choices. We know that food choices can vary each day depending on changes in our daily routines.
To eat well and improve our diet we must have knowledge of nutrition and health science, and also take into account factors that influence our behaviour as well.
The evolution of nutrition science
SIMONE GIBSON :video transcript
It's really easy for people to get confused with all of the mixed messages out there. I think people are often hearing that they're told to eat one thing one minute and then told to avoid it the next minute. And so it leaves consumers finding it very difficult knowing who to trust, what information to follow. One of the reasons that this information is often changing is science is evolving. There is so much nutrition information out there. And there's a lot of mixed messages, because one minute we're being told that something is good for you and the next minute we're told to avoid it. And then a couple of years later we're told to eat it again. So yeah, it is really hard to follow.
Now one of the reasons for this is that science is emerging. We now have better technology, better designed experiments, and we're building on previous knowledge. Back in the 1920s malnutrition was probably more of an issue. So we were recommending different things compared to today's problems of obesity, cardiovascular disease, and certain cancers.
So also we've got to remember that our lifestyles are changing. We're not as active as what we were 50 years ago. And the food supply is very different to what it was 50 years ago. So of course we're going to have to start adapting what we need to eat as opposed to what our requirements were.In the past pregnant women were advised to liver because it was a really good source of iron and that might help with the baby's development. However we've now found that liver is a storage organ for vitamin A, which is actually toxic at high levels. So therefore we no longer recommend pregnant women eat high amounts of foods like liver.
So the guidelines are constantly changing for when we're meant to introduce certain foods to infants. And that's partly due to the rise of allergies that we're finding in children these days. So it's really important to talk to your health professional about when to introduce certain foods and not just rely on what your mum says, because that's what she did, and you're perfectly fine.
So eggs have always being considered healthy and beneficial, high in protein, high in energy. But then in the '70s there was a bit of a backlash against them because they contain cholesterol. And everybody was trying to not eat cholesterol because cholesterol was believed to make your blood cholesterol high, therefore increasing your risk of having a heart attack. Now we've found that it's actually saturated fat that more influences cholesterol levels rather than cholesterol intake itself. And therefore we've re-evaluated our advice about eggs and we see that eggs are actually OK. They have a good spectrum of healthy fats. They're high in protein. They're low in saturated fat. So we do recommend that people have them.
So it is important to pay attention to the latest guidelines. By knowing the latest information it means that you've got the most up to date recommendations that are based on where our population is at now, the kind of food supply that we're getting our food from, and the kinds of diseases we're trying to fight against.
Nutrition research is continually emerging with very exciting new results.
However, it is important to treat new information with some care. You need to know where the research was done? Has it been repeated by other research workers? Was it carried out on people like yourself?
Be cautious in evaluating new nutrition information
It is important to recognise that many new nutritional studies are not performed in large groups of the general population. This would be far too expensive. Instead many studies are done on population sub-groups especially on people at high risk of common disease conditions such as heart disease.
Results in these people, while often useful and interesting, may be different from the results you would get on others in the population.
Other studies may not be done in humans at all but may be carried out in different kinds of animals such as mice or pigs. These animals have different digestive systems from humans and so results may again be somewhat different from those that would occur in a healthy human.
Many studies both in humans and animals are done using specific foods or extractions of nutrients. Yet humans eat mixed diets and not single foods. So how an extract behaves when it is eaten alone may differ from the effects when it is eaten as part of a mixed diet. In particular, the dose or amount that is eaten in one day may be very different from the dose or amount used in an experimental study.
We need to be very cautious applying and generalising results of new nutritional studies to larger population groups and especially to the general population.
Nutrition in the media
The media is usually very interested in reporting new and interesting nutrition and food news and often reports the findings of new studies.
Let’s examine a recent reporting about coconut oil. An article in an Australian newspaper reported that scientific researchers had found that coconut oil:
is easy to digest
helps prevent insulin resistance.
The newspaper article explained how coconut oil can be added to your diet by “adding one teaspoon of coconut oil to your usual intake each day, slowly increasing to four teaspoons to help with weight loss”.
What is the problem with this information?
Firstly, readers are not given much background information about this study. From the details provided it was not possible to trace the original paper where this study was described.
What other information is missing that would allow you to determine whether this is reliable advice?
A comparison with nutrition findings in a scientific article
The newspaper article also referred to a second study stating that coconut oil:
protects against insulin resistance
reduces the risk of Type 2 diabetes
contains MCFA (medium chain fatty acids) that can reduce the amount of fat we store and improve insulin sensitivity.
Why shouldn’t you follow newspaper reports?
While again the results are very interesting, there are many reasons why it might not be helpful for you to apply to your diet:
The study was carried out on highly inbred strains(교배개종) of mice and rats (C57BL6/J and Wistar strains, respectively) that may differ somewhat in their digestion and metabolism(물질대사) from humans. Also only male rats were used in the study so more evidence is needed on what happens in females.
The diets fed to these mice and rats were enriched with long and medium chain fats extracted from coconut oil (for the test group) or from lard (for the control group). These extracts were added to pellets of basic rat and mouse feed. So you can see that the experiment did not examine the effects of whole coconut oil and it did not examine the effect of coconut oil as a component of a human-type diet.
In addition the mice and rats were fed very high levels of the coconut oil or lard extracts. These extracts provided 45% to 60% of total energy which is at a much higher level than would be present in most normal human (or rodent!) diets.
The mice and rats were fed their experimental diets containing coconut oil for only 4 to 5 weeks. This does not tell us whether it would be beneficial or dangerous to continue this diet over an entire lifetime.
Research findings
At the end of the experimental diets, the authors investigated the effects on specific serum(장액) and tissue markers in the rats and mice. They found that the experimental diet improved some markers relating to insulin use and that it also reduced body fat in the test animals.
However, the authors also give a warning that wasnotnoted in the newspaper reports “Unfortunately the downside to eating medium chain fatty acids is that they can lead to fat build up in the liver, an important fact to be taken into consideration by anyone considering using them as a weight loss therapy.”
So you can see that a scientific study that was well carried out and reported in a well regarded scientific journal has not been very well explained in a subsequent newspaper article.
