My new doctor said something the other week that made me think. After seeing a sample food log, he commented that I wasn’t getting enough protein in the morning and was eating too much at night. For example, I would have 2 eggs in the morning (12g) and 10 oz of steak for dinner (70g). My first response was “What’s the big deal? It all adds up to the right amount by the end of the day.” … But do the day’s totals really matter to your body?
The body is constantly using nutrients, e.g. fat, protein and glucose, etc. It doesn’t wait until the end of the day when everything is totaled up, a deficit is noted and any shortage is made up from storage.
Instead, fat is always flowing out of your fat cells into your blood (or coming in from food) making itself available to be used and then moving back into your fat cells. Similarly glucose circulates in your blood, coming in from many sources (food, stored glycogen, gluconeogenesis) and can be restored if unused (though this is broken in diabetics). The same is true for many micronutrients, e.g. vitamin C. So where is protein stored?
Here’s the rub, there is no inert storage form of protein; it is used to build muscle, bones and organs. Your tissues are continually breaking down its protein into amino acids. From there they can either reuse those amino acids to rebuild what was just broken down, they can take even more amino acids from your blood and build bigger or they can release those amino acids back into your blood for other organs to use. And any excess protein? It doesn’t magically cause your muscles to get bigger or your bones stronger. Once your body has used as much as it needs, the rest is usually converted to glycogen (a form of stored glucose).
Keeping this in mind, when I eat a protein-light breakfast, a moderate lunch and go all out at dinner, what does that look like to my body?
- In the morning, I have been fasting for 12 hours, I’m already pretty low on amino acids and since I didn’t get much for breakfast, my cells are most likely to give up protein (for the sake of more important organs like the heart).
- At lunch I get a good dose of protein, raising my amino acids levels and enabling my cells to use them to rebuild and retain protein.
- Now for dinner, I have my mega-steak (yum!). I get a huge influx of amino acids and my cells can use as much protein as they need to rebuild. But they only need so much, and the excess isn’t stored as protein. Instead my liver helpfully saves it for a rainy day as … glycogen. Which can then be used later to raise my blood sugar.
My day’s total protein was right on target but now not only am I losing muscle and bone mass but my fasting blood sugar is getting higher! After all I’m giving my liver plenty of ammo every night with that excess protein. So while it all looked good on paper, my carefully planned meals weren’t having the effect that I had hoped for…
So from now on, I’m saving that extra steak at dinner and eating it at breakfast. Yup, with advice like this, the new doctor should work out just fine.
- I don’t have solid references or citations for this stuff. It’s what I learned from my doctor, so if it is incorrect or you have some good references, please let me know!
- Though I’m focusing on protein, there are equally good reasons for splitting all of your nutrients evenly across your meals. Especially if you are diabetic, you should avoid lumping all your carbs into a single meal.
- If you are eating very low-carb, your body will also use protein and convert it into glucose for your brain, via gluconeogenesis. This is why it’s very important to get adequate protein from your food. If you don’t your brain will win every time and you will lose lean body mass.
Check out How Much Protein Should You Eat? for information on how to calculate out how much protein you need.