Longevity 101 and the Science of Burning Fat for Fuel

I listened so you don’t have to!

Shawn Stevenson on his Model Health Show podcast interviewed Mark Sisson, a former triathlete and fitness author, on his best advice for longevity and some of his best hacks to live longer in good health.

• Mark Sisson, age 69, looked to be in fantastic health and still is very active in sports. He started Primal Kitchen, a company offering healthy versions of favorite sauces and condiments.

Mark was asked to name the three best foods for longevity but responded first with the three top things to avoid, which he claimed is even more important:

• industrial seed oils;

• sugary beverages; and

• processed grain products.

Mark noted that the three best things to consume are quality protein (including beef); healthy fats (including avocado/avocado oil, olives/olive oil, fish); and berries (particularly blueberries, but really all the berries). He did suggest, however, that we be as inclusive as possible in our diet.

Mark noted that building and maintaining muscle mass is one of the most important things people should focus on for healthy aging. He even went on to say that after age 45, your primary “job” should really be to maximize muscle mass because of the benefits muscle brings to mobility, strength, and bone density as you age.

• He argues that eating protein and practicing strength training are the two best ways to maximize muscle mass. Besides muscle mass, liver strength and aerobic capacity are the primary determinants of healthy aging.

Mark popularized the term “metabolic flexibility” which means the ability of your body to make energy from glucose, fat stores, and ketones (a byproduct of fat metabolism).

• We don’t want to be burning our protein; it is structural and used to build tissue and muscles.

• Your liver and muscles know how to burn fat but we need to train the brain to burn ketones for fuel.

If you are metabolically flexible, in the absence of glucose, your body can burn excess fat, while preserving muscle mass, and maintaining optimal energy and immune function.

If you are not metabolically flexible (and only 12% of the US population is metabolically flexible), the brain only knows how to burn glucose.

• If you are not metabolically flexible, when you miss a meal, the brain freaks out, sending signals to the adrenals to release cortisol so that the cortisol can go strip amino acids from the muscles to fuel the brain. The amino acids get sent to the liver to make glucose to send to the brain to make it happy.

You need an optimum amount of protein (between 80-120 grams depending on your size) to maintain and build muscle. Mark argues that you don’t need to eat a certain amount of protein at every meal (you can spread it across the day or longer) if you are metabolically healthy; you can even shoot for protein averages across the week.

The ideal type and amount of exercise we need as we age may be surprising. Mark focuses on a lot of low- level activity, suggesting about 5 hours a week of walking. He also suggests lifting weights two times a week and sprinting one time a week to your maximum heart level in 30 second sprints (4-6 sets), with 1-3 minute rests in between.

• The sprints can be running sprints but also intense swimming, biking, the stair master, the elliptical, or any short, intense workout. The key is to use as many body parts as possible for 20-40 seconds at a time.

**Content provided for educational and informational purposes only. It is derived from an interview of Mark Sisson by Shawn Stevenson and is not to be considered medical advice.**