It might not make your life shorter but it might make the later years of your life miserable. The fact is all margarine does not taste like crap and avoiding bypasses, angioplasty or heart transplants in the future might just be worth it. My Dad had the same idea about margarine, ate butter like it was going out of style and he had a massive heart attack and died at 60. Reminds me of those that smoke saying the same kind of thing.If my life is a little shorter because I prefer butter, then so be it. Margarine tastes like crap.
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I would suggest trying different brands of margarine because some are about as close to butter as you can get. Butter is almost 100% animal fat. In moderation it is fine but if you can subsitite something almost as good tasting and better for you, why not?