A guest post from Jenny Scoville Walsh with wonderful advice on losing weight.

A lot of people are planning on setting weight loss goals for the New Year.  I set that goal this year and I’m succeeding!  Over this year, I not only lost all the weight I gained in med school (all that sitting to study and munching to stay awake did a number on me—we just won’t discuss WHICH number), but I also lost some beyond that.  And so next year’s goal is “keep up the good work.”  I’m going to tell you what is helping me and maybe it will help you.

First, whenever people talked about metabolism (pre-med school), it sounded like this nearly magical thing that if you were lucky it was fast, if you were unlucky it was slow, and if you weren’t careful you could ruin it.  However, metabolism is simply the sum of all of the processes in the body that build (anabolism) or break down (catabolism) things in the body.  (see my video on Metabolism on Youtube.  I’m Englishgalmd)  It isn’t magic and you can’t break it.  It is something you can understand well enough to make better lifestyle choices and lose weight.  It IS true that you can have a faster or slower metabolism based on a lot of things (like thyroid hormone levels, for example).  If you’re losing hair, getting fat, feeling weak, tired, and depressed, have dry skin  and brittle nails, experience constipation, cold intolerance, or loss of the outer 1/3 of your eyebrows ( you  can Google “hypothyroidism”) get that checked out!

If you’re overweight, you probably hope you have hypothyroidism, because it can be treated and as a result, it will be easier to lose weight.  However, most people who are overweight do not have hypothyroidism.  They have a math problem which is causing their weight problem.  This is the math problem:

(Calories in-Calories out)/3500 calories per pound=change in weight

Let’s break that down.

Calories in-Calories out=change in calories

If you take in more calories than you use, your body with have extra calories to store as fat.  If you take in LESS calories than you use, your body will have to use extra calories from fat (I’m saying this with caveats attached—see later) and you will have smaller fat stores.

Now, let’s examine the other part of that math problem.

Change in calories/3500 calories per pound=change in weight

If you take in an extra 3500 calories, (and a pound of fat is 3500 calories), then your body is going to store 3500 calories, or you will gain one pound of fat.  Even if you are eating only protein, you will still store extra calories as fat, because fat is the storage molecule.

There are ways to make this math problem more complicated, like you could exercise or live in a very cold climate or have a higher percentage of muscle.  And you may, if you’re building muscle, WANT to gain a pound of muscle which you’d do by working that muscle and then providing the proper amount of protein so when it rebuilds itself, it can be larger.   You might temporarily change your weight with extra bulk in your intestines or being very hydrated or dehydrated, but your body will normally balance those things out.  You might be retaining water somewhere if you have swelling at your extremities or have a sudden change in abdominal size.  That’s not a calorie problem and you should get that checked out by a doctor.

You could decide to not eat at all and live off your fat, but DON’T DO THAT!  Living only off your fat causes a lot problems, since your body still needs some glucose (it is your brain’s preferred food and the only food red blood cells can use), and fat can’t convert back into glucose.  The only way your body can make glucose once the glycogen stores are gone (after 24 hours of not eating glucose sources) is to break down protein in your body.  Protein is not a storage molecule.  You are using all of your protein for muscles, carrier molecules, enzymes, coating your nerves, etc.  So basically, you need some source of glucose to at least feed your brain and keep a few processes moving properly in your body.  However, you can use fat to fuel many processes in your body.  In addition, you need various vitamins and minerals.  Take a multivitamin, but realize that food sources are usually MUCH better than taking a vitamin pill, so please don’t starve yourself!

So, the equation can get really complicated, but fundamentally, it can help to think about how to manage the calories taken in or calories used.  Excess calories (the stuff you don’t need to build your muscles, repair things, move, maintain your body temperature, and perform all of your normal body processes) will get sent to fat cells and stored as fat.  And, as long as your body has enough glucose to do its job and enough protein to repair itself, then eating less calories than you use will lead to weight loss (mostly from fat).

The next thing I learned is that one part of the equation is actually a lot more important than the other.  Calories IN can change a lot faster than calories out.  If you don’t believe me, go check out how many calories various exercises burn in an hour.  Then compare that to how much junk food you could eat in an hour.  You can easily outeat your exercise capacity.  So, be wise with what you put in your body in the first place.  Don’t get me wrong.  Exercise is great!  You tone your muscles and help your heart and lungs function better.  If you do weight bearing exercises, it can make your bones become stronger.   It can release natural endorphins.   It can even give you 200-400 extra calories to play with in your calorie equation.  However, it cannot undo an extra 2,000-3,000 calories every day unless you also run a marathon every day.   And I notice if I work out VERY strenuously, I am ravenous afterward and also take it easy for the rest of the day.  That doesn’t help my cause, you know?

So, how many calories ARE you taking in a day?  You can get some pretty good estimates with calorie counters.  There are TONS of them online.

Calories out is trickier.  There are estimates on line for different exercises you do and your general activity level and how tall you are and your gender.  If you don’t want to mess with that, just weigh yourself every day and then see if you are going up, going down, or staying the same.  If you can maintain your weight on 1800 calories, then you know how many you are burning daily, right?  If you’re gaining weight on 2200 calories, then you already know you need to back off on your food intake because you don’t need as much as you think you do.

Now, here’s how to use the equation for good.  Let’s say you know you maintain your weight taking in 1800 calories.  You don’t have to do anything super drastic (especially if you’re nursing a baby or pregnant or still growing up).  Just try USING 1900 to 2100 calories.  How?  Move a little more. OR, you could TAKE IN 1500 to 1700 calories by eating less food at lunch or dinner and fill the rest of the way up with water.  Eat half the dessert you normally eat.  Cut out a splurge a week or chew sugar free gum instead of pretzels when you want something to munch.  You could cut out more, but if you cut out too much (like going down to 1 meal a day, or taking in less than 1200 calories a day) first of all, you start bringing in some of the more complicating parts of metabolism which I glossed over (getting enough glucose to make your brain function properly without using up all your body protein, being nice to your kidneys by not breaking down too much protein a day, etc.).  But, second of all, you’re setting yourself up for an unworkable long term plan.  If you’re planning on losing more than just a few pounds, it’s going to take a while.  I’ve been working on weight loss since January and I will be working on it for at least several more months.  There is NO WAY I could do it if I were starving myself, eating only the foods  I hate, or working hard to always bring limited foods I’m allowed to eat with me.  My perspective is, do it in a maintainable way.  If you do something really drastic (even if you somehow aren’t hurting your muscles and kidneys), you won’t be able to stand it for very long and then you’ll revert.