This is based on For the heart’s sake: eat a variety of fats and let the body choose, written by Dr Stephanie Seneff PhD. This can be found on pages 40 & 41 of this month’s issue of CAM: The magazine for complementary and alternative medicine professionals, a complementary & alternative medicine magazine to which I’ve been subscribed for 5 years. I used to do Nutritional Therapy at uni, and though I’m not a nutritional therapist I still maintain great interest in the topic. I have also added in other parts from my general knowledge.
We in the West are given conflicting and even downright wrong information about fat. Just to be clear I mean dietary fat, not body fat. We’re given the message that although omega 3 fats are healthy (true), saturated fats are bad for us (untrue) because that’s what health experts, government guidelines, TV ads, etc. drum into our heads. Same with high fat intake in general & cholesterol. However, the research has never (and I mean NEVER) proven that. In fact, the research overwhelmingly suggests the opposite: high intake of general fats* and saturated ones especially protects against cardiovascular diseases.
* fresh naturally-occurring fats. Rancid fats, as well as hydrogenated & trans fats, absolutely are linked to cardiovascular diseases, infertility (at least in women), obesity, type 2 diabetes (the worse kind), liver dysfunction & even Alzheimer’s.
WARNING! If you find long wordy explanations death-inducingly boring skip the red writing. Don’t want to look like this guy!
Fat molecules (fatty acids or lipids) are of different types: saturated & unsaturated, or as I call them satted & unsatted. The difference is in molecular structure – the satted ones contain no double bonds between their carbon atoms and are thus chemically stable. They’re called saturated because the chain of carbon atoms is bonded to the maximum number of hydrogen atoms it can hold. Unsatted ones contain double bonds. If there’s only 1 double bond the molecule is called monounsaturated (what I’ll call munsatted), and if more than 1 it’s called polyunsaturated (what I’ll call punsatted). The double bonds mean there’s still space for hydrogen atoms to bond, and the more unsatted the fat is the more vulnerable it is to going off (rancid). Pretty much all plant fats are rich in unsatted fats, hence why plant fats tend to be liquid except coconut & palm oil. Animal fats tend to be more satted fat-rich and thus more solid, except marine animals like fish & shellfish. Due to the rancidity risk, it’s better to have antioxidant-rich foods (such as fruit & vegetables) along with unsatted fats, although they have their own benefits in the body.
(Note: satted, munsatted & punsatted are just names of groups of different fats. In each group are many many individual molecules with small but often important differences in atomic constituents, which I won’t list here for brevity’s sake. In case you were wondering, the omega 3s, 6s, 9s & others are all punsatted)
Trans fats are unsatted fats heat-treated to become saturated, to increase shelf life (ie. delay rancidity). The heat treatment is called hydrogenation because they’re adding hydrogen atoms to fill the double bonds. However, the hydrogenation also alters the natural arrangement of carbon atoms, turning the configuration from cis to trans, especially if the process is incomplete which it often is. This means the whole lipid is in a shape the body can’t recognise so it will try to get rid of it. If it can’t, though, it accumulates in the body as waste because it has no function. It’s useless! Our bodies have no requirement for trans fats but unfortunately they’ve become ridiculously common: in near enough all fried foods (because they only use unsatted-rich oils. Satted ones would be healthier but your typical local chicken & chips shops don’t care), processed foods in general, biscuits, cakes, pastries, that sort of thing.
Structural difference between natural cis (left) & unnatural trans fats (right). The C=C’s in the middle symbolise the double bond, thus this is a munsatted lipid…
… and he’s not bothered
We’re told by the authorities to reduce our total fat intake to 20% of our total calorie intake. This is misguided advice because:
1) most people wouldn’t be bothered to calculate their calorie intake,
2) calorie requirements change according to age, sex, health & activity level,
3) it’s not calorie amounts that matter but calorie sources. Calories from fats, carbohydrates & proteins have different metabolic effects,
4) low fat intake is shown to be correlated to increased risk of infertility, coronary artery disease & other cardiovascular diseases. Conversely, high fat (especially satted fat combined with fruit & vegetables) is linked to lessened risk of them.
However, the really interesting part is what Dr Seneff proposes in her article. From research done on mother rats (not done by her), she proposes that the body should be fed more fat because the body can pick & choose which fats it needs for what. As long as it can be broken down for energy, the excess fats should be no problem. The body is much more sophisticated than we think.
Summary: fresh natural dietary fats are good for you, and percentage of total calorie intake is not very important. This low-fat fad is not just misguided but risky, so it’s far sounder to avoid trans & hydrogenated fats rather than fats in general.