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Why Too Much Protein Can Slow Your Metabolism

In yesterday’s post I blogged about how potassium from fruits and veggies plays a role in building and maintaining muscle and bone. Here’s a little more about how that works:


There are three major ‘macronutrients’ – carbs, protein and fat. In a nutshell the job of carbs is to fuel your cells, like gasoline in a car. Protein isn’t meant to be used for fuel. Its primary job is to repair, regenerate and heal cells in your body, from muscle and bone to immune cells, hair, skin and organs. Fats do a little bit of both.


Every day there’s a limit to how much fuel your body needs and a limit to how much healing and maintenance your body requires. When you eat more than needed the excess either feeds your fat cells or makes them larger. When you eat too little some “jobs” in your body just don’t get done, and that’s why undereating can lead to fatigue, a loss of muscle mass and a weaker immune system. Good nutrition is all about striking the right balance.


When too much protein is consumed your body will either burn it or store it. The former typically happens when people cut back on carbs and eat more protein. In other words protein must become the fuel because carbs (the preferred fuel source) are in shorter supply. Or if adequate carbs are available and there is no need to burn the excess protein for fuel it will be sent to your fat cells.


In either case a side effect is the build up of nitrogen, part of the protein molecule that can’t be burned or stored (this isn’t an issue when protein is used for repair and maintenance). This build up is what contributes to the acidic state I referred to yesterday, which can lead to the breakdown of muscle and bone. And again, that’s where potassium comes in, to buffer that acid and protect your body’s lean tissue.


To stay in balance, preserve muscle and bone, keep your metabolism revved up, and give your body enough potassium I recommend a two step approach. First incorporate fruit into breakfast and snack meals, veggies into lunch and dinner meals and second, if you’re an omnivore, stick with moderate portions of meat and seafood, about 3 oz per meal, the size of a smart phone or a deck of cards in thickness and width.


These 7 foods are rich sources of potassium. The amounts listed below add up to over 4,700 mg, the recommended daily intake. That doesn’t mean you have to eat all of this each day, it’s just an example to show you how much potassium various fruits and veggies pack (notice bananas aren’t the highest):

Potato, baked – 1 medium - 1,081 mg

Lima beans – 1 cup – 955 mg

Spinach, cooked – 1 cup – 839 mg

Pistachios – half cup – 630 mg

100% orange juice – 1 cup – 496 mg

Bananas, fresh – 1 large – 487 mg

Prunes, dried – half cup – 414 mg


So do you think you get enough produce or too much protein? Did you know that an excess amount of protein could actually cause muscle to weaken? Please share your thoughts!



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