Is there still a debate between the two? As i've heard different opinions.
For me it's not a debate
I eat a stack load of butter and my cholesterol is way down. I'm just not a fan of processed food. I try and get as much natural produce in me as possible - hence why my shopping bills are so high - unjustifiably so, I think it's our right to have good quality food for little cost. But that's another debate!
They both have the same amount of calories gram for gram but butter is slightly higher in saturated fats around 20% more gram for gram - so not a huge amount really.
Butter has actual nutritional benefit, whereas margarine has only a few and only owing to being artificially added ot them.
Butter has done us well for many many many centuries, so why change to something synthesised and almost nutritionless? Furthermore, marg is high in TFAs - which isn't good as this could potentially increase the risk of CHD.
Whilst the claims for lowering cholesterol, I don't believe it, or if it does, it decreases HDL as well which is pointless as the ratio between LDL and HDL is more important the ratio should be above 0.4 of HDL/LDL - this again is another link to heart disease.
In women, it potentially can lower the nutritional quality of breast milk owing to it's TFA content.
There are also quantifiable measurements of marge decreasing immune and insulin responses, however these were extreme tests with bad diets and large amounts of marge - however these were owing to large amounts of TFAs which are more present in a lot of marges - not all nowdays, as you're probably away a lot of them have started to use butter in their marges because they realised that marge by itself was poor.
As you know, my keeness on insulin response and activity within your body, certainly for bodybuilding is quite a thing of mine - so anything that interferes with that goes bye bye out of my diet!
Again a lot of the above is for a high amount in your diet - but why even put it in your diet in the first place?
There's also the debate on taste - I look good food, and butter tastes great! There are some weird "facts" out there like increasing risk of cancer etc... ,but I'm not bothered about them - I'm more interested in the actual ins and outs of butter.