Low methionine intake has been shown, in animal studies, to mimic many of the same effects of calorie restriction, which is to say improved health and extended life span. A sizable fraction of the trigger mechanisms that produce improved metabolism as a result of lowered calorie intake appear to depend on methionine levels. Attempting a reduced methionine diet is about the hardest thing that any casual health enthusiast could choose to undertake when it comes to dietary self-experimentation. The sources of data on methionine content are incomplete and contradictory, and just about every common food stable is packed full of methionine. The specially formulated medical diets for people with conditions that require very low methionine intake in order to avoid pathology are expensive and unpleasant to consume in comparison to normal food. But perhaps there is a better way forward, and, given time, we may start to see low methionine options becoming more affordable and palatable.
"We've known for years that restricting the amino acid methionine in the diet produces immediate and lasting improvements in nearly every biomarker of metabolic health. The problem is that methionine-restricted diets have been difficult to implement because they taste so bad." Until now. Restricting methionine normally involves diets formulated with elemental (e.g., individual) amino acids. Individual amino acids are the building blocks of proteins. But diets made from elemental amino acids taste bad, and few are willing to tolerate the regimen.
A palatable solution emerged from the development of methods to selectively delete methionine from casein, the main protein in milk and cheese. Researches conducted proof-of-concept testing to establish that oxidized casein could be used to implement methionine restriction without the objectionable taste of the standard elemental diet. More than two-thirds of Americans are overweight or have obesity. More than 40 percent of adults have prediabetes or type 2 diabetes. A diet that offsets all the major components of metabolic disease would have an enormous impact.
A palatable, methionine-restricted diet could also ease a major frustration for those struggling to manage their weight. Each year, millions of people improve their metabolism and lose weight by reducing how much they eat. But eventually, most people gain back those pounds.