Only around 1% of Americans are vegan, which means avoiding any food product related to animals. Researchers decided to check out the benefits of avoiding meat and more by looking at 22 sets of twins — one put on a healthy vegan diet, one on a healthy omnivore diet — to assess the impact.

The eight-week study explored how those two diets turned on or off each twin's epi-genes, which respond to environmental impacts and influence biological aging.

The researchers discovered that a vegan diet makes changes to molecular markers in genes that determine what time it is along a person's journey toward older age.

In all, they found 12 "clocks" that indicated the vegans were headed toward a younger biological age. The meat-eaters just got older.

You may not opt for a vegan diet (Dr. Mike would never give up salmon), but you can be guided by this additional evidence that what you eat has a huge impact, very quickly, on how you age.

So ditch all red and processed meats, opt for skinless poultry and fatty fish, and eat seven to nine servings a day of fruits and vegetables.

That will switch on your health-promoting epi-genes — and make your jeans fit better too.