Have you heard about the diet experiments in which animals can be made to live longer than their normal lifespan? The only problem is that the diet used is essentially a starvation diet- the animals are fed much less than normal for their entire lives. Personally I am not looking forward to the discovery that a starvation diet will also allow humans to live longer.
But there is hope- cutting out one little nutrient (while eating normal amounts of food) also allows animals to live longer lives (and be thinner), and that nutrient is methionine. Methionine is an amino acid, one of the building blocks of protein, and it is essential for life, but perhaps in smaller quantities than we usually eat.
Now for the type of wild speculation that I usually make fun of- would it be good for us to eat less methionine and how would we accomplish this? Methionine is high in grains and seeds, moderate in animal foods (milk, meat, eggs) and corn, and low in beans, nuts, soy, and peanuts.
Would it make a difference to cut out grains (wheat, rice), eat less animal products, and eat more legumes? You would not be able to achieve the low methionine intake that has been found to work in animals, and amazing results in animal experiments almost never translate to useful recommendations for people, but it’s something to think about.