Thank you for your kind comments and interest.
Thanks Rhonda for the links. The Mateljan site was particularly well laid out, and from a quick skim is informative.
Re the questions as to how much - as usual no easy answer but in essence from what I have read so far
1...**** BALANCE the Omega 3 and 6
plant based fats with a ratio between 1:1 and 1:2. We only need between 1/2 - 2% of calories (Issfal suggests 2-3%). There is not a simple way to do that except look up the fat content of the foods you eat and try and estimate your intake. The vast majority of processed food will contain vegetable fat even some processed dried fruit! - So check lablels.
2. Get at least a gram and up to 3 grams combined total of the long chain Omega 3s DHA and EPA from oily fish or fish oil. Women and men have different needs it appears. Women make DHA better than men and need more of it. (Our shore dwelling ancestors would have eaten more Omega 3 than 6 as fish and shell fish are much higher in Omega 3 than 6.)
Fish and shell fish are a good source of minerals and iodine.
Minerals in food have dropped by between 20 and 70% due to soil depletion in the last 50 years.
Do remember to have a look at the content of fish oil as it contains a whole range of fats which may help inform you other intake. Check the A and D content of fish oil and make sure you are neither overloading or getting too little. Some manufacturers remove D or A or both.
If you feel it appropriate to take GLA remember it usually comes with omega six and work that into the balancing act. As usual looking for a food source might be a better option. I am less certain as to where GLA sits in the pecking order, and less is written on the series one products and the extent to which the body will produce GLA.
http://cpmcnet.columbia.edu/dept/ihn...lides_2005.pdf
This link provides some graphs which seem to suggest 2 grams of DHA a day is the level at which take off drops off, BUT I would guess it would depend on what the omega six intake was, the composition of stored fats, individual metabolism etc. ( about 4 to 5 tps of a reasonable quality fish oil or equivalent in algae source). I am taking 2grams as a minimum some times more and just trying to assess how I feel changes in body function, fitness, weight, liver function etc.
I am afraid that there are simply no absolute answers and the research has not been done.
Side effects are limited but do exist at higher doses so check with your advisor particularly if on medication. Blood thinning is the most common issue.
Other than the fish oil, use maybe a little olive oil or other low Omega 6 oil maybe 1 tablespoon a day. Moderate use of grass fed butter is fine (vit A D K etc). I do not use any oils margarines etc, but it is very much a personal choice. In hunter gatherer terms our access to omega six was limited so my guess is less is better eg give up margarine etc. There are no easy answers and until they trial outcomes v changes in adipose fat content in a sufficient number of people we simply will not know.
I hope that helps I am sorry I cannot be more specific at this time.
I will post separately on sources of omega three and six in so far as I can.
RB