Showing posts with label fat. Show all posts
Showing posts with label fat. Show all posts

Wednesday, April 27, 2011

Dairy, dairy, quite contrary

I’ve already written a bit about dietary fat and some of the evidence that it’s not the demon in our food supply that we’ve been told it is. It keeps coming up though. For example, let’s see how fat is portrayed in the 2010 USDA healthy eating guidelines. These guidelines emphasise the need to eat ‘nutrient dense’ foods, where:

...the nutrients and other beneficial substances in a food have not been “diluted” by the addition of calories from added solid fats, added sugars, or added refined starches, or by the solid fats naturally present in the food.

Yes, I added the emphasis. I thought it needed emphasising. And in case you are wondering, yes, they are suggesting that, for example, milk can only be considered ‘nutrient dense’ (and therefore good for you) if it has had the fat naturally present in it removed. On the one hand, this is not a surprise- it’s the usual ‘fat= bad’ message. But...it is surely a strange state of affairs where changing a food source from it’s natural state is considered a healthier alternative. 

At some point I want to look at how we got to this point where a ‘good’ food is one that is stripped of its natural contents. The history of this is really interesting- lots of twists and turns, bad science, good science with bad interpretations, intrigue, politics and murder. Well, ok not murder. But death from heart disease does feature. You’ll have to wait for that one, though. 

For now, let’s just focus on dairy. Why? Well, I can’t help but feel sorry for dairy. I think it got shafted in the whole low fat movement, to be honest. We were told to fear saturated fat and its partner-in-crime, cholesterol and dairy is full of both. The dairy farmers must have been spitting when the Heart Foundations and nutritional ‘experts’ started calling for people to leave the full fat milk where it belonged- in the cow. Here they were selling a product high in calcium, protein and vitamins and completely natural, and it suddenly wasn’t good enough. 

But then they rallied, perhaps realising that they would now be able to sell two products instead of one- low fat for the health conscious, and full fat for the rebels. 

While milk, cream and cheese got the low fat treatment, butter was thrown out the window altogether. Actually, it had been on the way out for years, with the support of the Heart Associations who pushed margarine with their mono and polyunsaturated fats made from natural plant seeds as a much healthier alternative. The Butter V Margarine fight is billed for another day- it deserves it’s own post. Let’s think about milk, cheese and yoghurt.
Does removing the fat from a glass of milk really make it more nutritious? 

Milk (the basis of all dairy, remember) contains vitamins A, D, E, and K, among other things. These vitamins (useful for seeing, preventing rickets and absorbing calcium, protecting cells from damage and helping your blood coagulate so you don’t bleed to death, respectively) are fat soluble. The less fat there is in the milk, the less you get of these little helpers. Talk about throwing the baby out with the bathwater (something you should never do). Here’s a little chart to illustrate this point- based on the values on this fabulous site.



You can of course fortify your skim milk with vitamins after you take out the fat. This is actually mandatory in some countries in order to make skim milk as nutritious as it was when it had the fat in it. It’s a good marketing tool in other countries- Rev can plaster ‘with Vitamin D!!’ all over their cartons, thus making it look like they are doing us a favour. 

But even if we ignore the vitamins (the oh so essential, fat-soluble vitamins), there are other important reasons to consider letting full fat dairy back in our fridges. Here’s a recent study from Australia which looked at the association between total dairy intake and mortality. They found that 
There was no association between dairy intake and death (you weren’t more likely to die if you ate more cheese), but
People who ate the most full-fat dairy were the least likely to die from cardiovascular disease.

The authors seemed quite surprised by this finding, and didn't really explain their findings except to say that more research was needed- but it’s one among many studies showing an seemingly inexplicable relationship between whole dairy and good health outcomes. Inexplicable because we expect a food so full of fat and cholesterol to do us nothing but harm. But here’s an example of another recent study from Harvard where they found that eating full fat dairy meant higher levels of a special fatty acid, which in turn meant better blood work (lower levels of bad cholesterol, for a start), and a lower risk of type-II diabetes. The people who had more of this fatty acid circulating around were also slightly slimmer. Since this fatty acid is (you probably guessed) found in the fat part of dairy, drinking your milk skim means you get far less of it. 

Nutrient dense? And how! I’m sure we will be hearing more about the benefits of milk in the future as we start to explore this from a 'dairy might be good' rather than a 'dairy is surely bad' perspective. 

We'll probably hear a big fat “I told you so” from the Dairy Council, too.

Wednesday, March 23, 2011

Fat versus fiction

I hope my research-y posts aren’t boring anyone that reads this. I’m finding it really fascinating to look into some of these things for myself- I think it’s the first time I’ve thought about nutrition in detail, even though I’ve thought about food, a lot. Feel free to post comments if you have any. I’d love to hear your thoughts.

I posted last about sugar and weight gain, but I can’t ignore the fat we eat when thinking about weight. I have always thought fat had more to do with weight problems than sugar. So, I use low fat milk, eat low fat cheese, ignore the crispy skin on my roast chicken and the delicious crackling on my roast pork. I limit gravy, fatty sauces, and fried foods. I choose the low fat tomato-y pasta sauce when we eat out, instead of the creamy sauce- I don’t think I’ve ever ordered the carbonara. I usually avoid things like potato chips for snacks, choosing lollies instead. Of course I sometimes eat high fat things (delicious camembert cheese springs to mind), but not without feeling guilty. But despite living this low fat lifestyle (with a few slip ups), I’m overweight. Boo. What to do about it? (Ignoring the obvious exercise question for the moment). Should I reduce the fat in my diet even more?

Doctors, nutritionists and the government have told us for many years that fat maketh the man (and woman) fat. We have been encouraged to keep our fat intake low, and as a result of this have increased our carbohydrate intake. After all, we need to get energy from somewhere, so we should ‘eat more breads and cereals’ as Norm learned in the Life Be In It ads of the 1980s (which you can revisit here if you like, thank you YouTube!) In case you think things have changed, here is Nutrition Australia’s current healthy food pyramid. Fats are in the top teeny part, and we are supposed to use even ‘low fat’ spreads sparingly. Although sugars share the top tiny portion (ie, we are supposed to keep our intake low), a study in 1994 showed that Australians who had the lowest fat diets had the highest intake of refined and natural sugars, not to mention alcohol. Oops. This won't surprise any of you who have already realised that most (if not all) foods manufactured to be ‘low fat’ have more sugar than their full-fat brothers. The sugar is added to make us think they taste nice, isn’t that great? As sugar has about half the calories per gram than fat, they can take out say 1 gram of fat and replace it with up to 2 grams of sugar without affecting the calorie content. So, a low fat meal is often a high sugar meal. Sneaky bastards.

As a former fat-a-phobe (phobic of fatty food, that is) I’ve come to realise that unlike sugar, fat is not an ‘empty’ source of calories. Fat is necessary for the body because:
It provides essential fatty acids
It helps us to absorb vitamins such as A, E and K which are fat-soluble
Our nerve fibres are insulated by fat, and fat helps to transmit nerve messages
Our cells all include some fat, which helps to transport nutrients from cell to cell
It helps our bodies to recognise when we have had enough to eat.

This isn’t all that fat does either. Fat is essential. Given the list above, a low fat diet starts to look a bit, well, stupid. Or, if that’s too harsh, then at least short-sighted, since we decrease one of the things that helps us to feel full and stop eating. On the other hand, there is evidence (for example, this study) showing that the fructose in sugar actually decreases our body’s ability to recognise when we are full by interfering with a hormone called leptin. So, fat says stop, but sugar says 'more'. I’ll look into that one in more detail later.

What about ‘bad’ fats- ie, saturated fats- surely I should at least be avoiding those? The Australian Heart Foundation suggest on their website that Australian’s decrease their intake of saturated fats because they lead to an increased risk of heart attacks and stroke. This has been the mantra of nutrition experts since about the 1960s, but is directly contradicted by a review published in the world’s top nutrition journal in January of last year which showed  that “there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD [coronary heart disease, which can lead to heart attacks] or CVD [cardiovascular disease which can lead to strokes]”. This finding came from a meta analysis of research, which is a combination of the studies in an area so that instead of say 10 smallish studies with say 10 participants each you combine the data to get the results for all 100 participants. This meta analysis included 21 studies spanning 29 years and had 347,747 participants. One of the co-authors,when interviewed by the Boston Globe put it this way: 'There is no evidence that cheese causes heart disease'. Hurrah!

So, I have started to make my peace with fat. It's been trying to do me some good, and I've been willfully misunderstanding it and trying to avoid it all this time. I’m having full-fat milk again, I think for the first time in my adult life, and I am loving it. It’s delicious! (Just as an aside, back in the day I remember this being called full cream milk- is it just me, or have we started to give it a much more negative sounding name- full fat??). I’ve completely stopped looking at the fat content of food before eating it. I feel like a rebel just saying that.

David Gillespie’s experience and that of others who have quit sugar using Sweet Poison has been that they get full easier and they stay full longer. They report that they feel the ‘fullness’ in a much more potent way than before. This might be something to do with letting fat do it’s job of letting us know when we’ve had enough, unhampered by sugar sneakily turning off the ‘I’m full’ button and triggering the ‘more please’ switch.

Well, I’m not there yet, so I’m off to eat some cheese, but it will definitely be minus the guilt :)