Blast fat 10x faster!

Using this wholesome cooking ingredient helps wake up a stalled metabolism to power off pounds. Kelly lost 133 lbs!

- LISA MAXBAUER

Here's a piece of weight-loss advice you don't hear every day: Be more like a fast-food restaurant. What?! Or at least consider upgrading from ultra-processed cooking oils to all-natural, unrefined fats like beef tallow. Old-fashioned tallow is trending, thanks to news that restaurant chains like Outback Steakhouse, Popeyes and Buffalo Wild Wings have embraced it, and women like Kelly Hogan, 46, are losing serious weight after switching. Here, the science behind the retro (and delicious) move and how it can work for you.

Our slim grandparents enjoyed full-fat cooking using this affordable, wholesome oil made from raw beef fat. And now some experts say it's time to go back to those old ways. "Modern diets are full of problematic fats," says Cornell-educated Catherine Shanahan, M.D., author of Dark Calories.

The fats she's referring to are highly processed, refined seed oils. They're nearly unavoidable in store-bought processed carbs and fried foods at restaurants, though some kitchens are now switching. Dr. Shanahan goes as far as to deem certain seed oils (corn, canola, cottonseed, soy, sunflower, safflower, rice bran and grapeseed) "the worst thing in our food supply."

How seed oils sabotage

"They promote something called oxidative stress, which my research shows is the root cause of literally every chronic disease, including metabolic disease and insulin resistance," says Dr. Shanahan, citing her 2025