Wednesday, June 24, 2015

Macronutrients: fats


Here comes my favorite macronutrient: fats. Or more properly, fatty acids.

This is for sure the most controversial topic in nutrition, that’s the reason why in this post I will just introduce some basic information and will dedicate the space required to be as comprehensive and exhaustive as possible for each point in another moment. I said my objective is to empower people and I believe this is particularly true when it comes to fats.

Types of fatty acids

Depending on their chemical structure, which I won’t discuss now, fatty acids can be classified as:
  • Saturated (coconut oil, red palm kernel oil, butter, dairy ghee, cocoa butter)
  • Monounsaturated (oil of olive, avocado, macadamia, lard fat)
  • Polyunsaturated ω-3 (oily fish, fat from grass-fed beef, flax/chia and relative oils)
  • Polyunsaturated ω-6 (nuts, pulses, seeds)
  • Trans/Hydrogenated  (margarines, spreads, butter substitutes, etc)
Fun fact: this is what margarine becomes if you hydrogenate it too much.

Important consideration

Any fat, butter or oil is made of a mix of different fatty acids, so the above classification is just indicative. For example, although coconut oil is made of 92% by SFA, making it the most saturated of all naturally occurring fats, there is still a decent 8% of unsaturated component. Other examples are less extreme however each fat or oil has a predominant component.

Good fats and bad fats?

The question is once again a trap: there is no such thing as a good fat or a bad fat. With the exception of trans and hydrogenated fats which are man-made and which I personally don’t consider fats at all but rather plastic, all the others are healthy in the ambit of a diet which includes them in a properly balanced ratio. This last observation is particularly addressed both to those readers who still avoid saturated fats because of some highly flawed studies from the 60ies, and to those who only use coconut products in their preparations because they are the trend now.

The way fats and oils are produced, stored and used in your preparations is also extremely important and makes quite a difference on how our body will respond. I will dedicate an individual post for each of them to discuss their nutritional roles and optimal use in the kitchen. With practical examples (recipes).

Essential Fatty Acids (EFA)

While our bodies can easily manufacture fats (I think I heard some sighs), there are some specific fatty acids for which we, as humans, do not have the instructions in our DNA to produce and therefore need to assimilate regularly through foods that contains them. They are the Linoleic Acid (LA, ω-6) and the Alfa-Linolenic Acid (ALA, ω-3). Some sources refer to them as Vitamin F, to enforce their importance.
Sources of LA include most seeds and nuts and relative oils, for example sunflower, safflower, evening primrose, hemp, walnut, sesame.
ALA can be found in chia seeds, kiwifruit seeds, flax seeds and flaxseed oil, or oily fish.

Some fatty acids are considered Conditionally Essential, they are DHA and EPA (both ω-3). Some people can manufacture them from the ALA but they apparently are a minority. Most people cannot or do it inefficiently: for them DHA and EPA are to be considered essential. The reason is still being investigated but the suspect is that there is a strong genetic component.
DHA and EPA can be found in good quality animal sources like grass-fed beef and oily fish.

Roles of fats in the body

Like carbohydrates, fats have long been associated with calories. That’s actually the reason people check how many lipids a yoghurt contains before buying it (big-big-big mistake!).
The existence of essential fatty acids and conditionally essential ones should already had planted a seed of doubt in your minds. That’s a good starting point because fats are not just 9KCal/g.
Roles of fats:
  • fats improve the taste of food, this should be enough to make anybody a fan
  • fats are a steady and long lasting source of energy
  • fats slow down the absorption of sugars (thus reducing blood sugar spikes)
  • fats satiate and reduce the tendence to snaking
  • fats are required for the absorption of fat soluble vitamins (A, D, E and K)
  • fats are a required component for the structure of the cells membranes
  • fats are required for the regulation of inflammation processes in the body
  • fats are the precursors of some hormones
  • fat constitute a cushion against shocks for internal organs
  • the fat layer in our body is also metabolically active and like a gland can produce hormones
In other words: fats are more than calories and are not negotiable if the objective is optimal health.

Final word for those who still don’t know: eating fats doesn’t make you fat (hint: sugars do). Yes, we have been lied all these years as I will explain in future posts so… stay tuned!

5 comments:

  1. Interesting post, thanks !

    Have a look at this article predicting low fat diets a things of the past:
    "Nutrition experts are hailing a federal decision to drop recommended restrictions on total fat consumption in the forthcoming 2015 Dietary Guidelines for Americans."

    http://www.newsmax.com/US/low-fat-diet-guidelines/2015/06/29/id/652617/

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    1. Exactly. Finally, after all these years! ;)

      I will dedicate a lot of posts on fats in the next weeks: which ones to choose and how to use them, the ideal ratio, etc.

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    2. That would be great ! I am particularly interested in the quantity limitations (if any) of consuming natural saturated fat (from butter, fatty meats, oily fish, etc).
      Many articles say that it is fine to eat saturated fat - but are there any limitations (apart from the obvious common sense ones). That would be interesting.
      Thanks for your articles !

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  2. Hi Alex,

    Good stuff with a lot of useful information. I'm just missing the link between the theory and practice. It would be good to have some hints and the common mistakes to avoid.

    Cheers,
    Franck.

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    1. Hi Frank,

      Thanks for your comment.

      You are right, these first articles are quite theoretic, but I need them before I can publish recommendations and recipes. I will link back to them every-time so to explain why I do things which sometimes may be against common wisdom (examples: why I don't fry in canola oil, why I have 4 eggs for breakfast, why I choose whole milk instead of skimmed, etc ;) ).

      I'm going to publish soon the first articles about traditional nutrient dense diets and food cravings. Stay tuned!

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