I know this is a little off topic but I have (in my advancing years) had an increased desire to understand how our bodies use food to fuel metabolism. What makes one person lose weight and another gain even with relatively similar diets. The article below from wikiHow explains how to compute your metabolic rate then ways to reduce, increase or maintain it. For the those of us that sometimes forget to get up from our computer chair and move around this is a must read. Enjoy this break from the normal tech article. (and join a yoga class or softball team or take up hiking or whatever your favorite activity might be to help maintain a healthly lifestyle.)

from wikiHow - The How to Manual That You Can Edit
If your trying to lose weight and think your metabolism might be the culprit, there are changes you can make to improve it. But with the commercialism surrounding “metabolism-enhancing” products, it can be hard to separate fact from fiction (or advertising) and pin down techniques that are scientifically proven to change one’s metabolism.

Steps

1. Understand what metabolism is. In the simplest terms, metabolism is the rate at which your body burns calories. The rate can differ from person to person. You and your friend can have the same activity level, diet, and weight but still gain or lose weight at different rates based on differences in metabolism.
2. Determine what is influencing your metabolism. There are some factors that you can change, and some factors that you can’t.
   • Age - metabolism slows 5% per decade after age 40[1]
   • Sex - men generally burn calories faster than women[1]
   • Heredity - you can inherit your metabolic rate from previous generations[1]
   • Thyroid disorder - problems in the thyroid gland can slow metabolism but this is rare[1]
   • Proportion of lean body mass - metabolism increases with muscle mass[1]
3. Calculate your resting metabolic rate (RMR). RMR is often used interchangeably with basal metabolic rate (BMR); although they are slightly different, estimating either is sufficient for the purpose of losing weight. To calculate your RMR, use the Mifflin-St Jeor equation (which is more reliable than the Harris-Benedict equation[2]). There are also calculators online that can do this for you:
   • RMR = (9.99w + 6.25s) - 4.92a + 166g
   • w = weight in kilograms; if you know your weight in pounds, divide by 2.2 to get your weight in kilograms
   • s = height in centimeters; if you know your height in inches, multiply by 2.54 to get your height in centimeters
   • a = age in years
   • g = gender = 1 for males, 0 for females
4. Adjust your diet accordingly. Your RMR will tell you how many calories you need to maintain your body at rest. Your daily consumption to maintain your weight should be:[3]
   • RMR x 1.15
   • E.g. RMR = 2000, so the maintenance intake is 2000 x 1.15 = 2300
   • To lose weight safely, consume no more than your maintenance intake but no less than your RMR.
   • Count calories by recording what you eat and looking up how many calories each food item contains (either on the food packaging or in tables provided in books or online).
5. Eat small, frequent meals. Extending the time between meals makes your body go into “starvation mode”, which means it’ll hold onto as many calories as possible and store them as fat. This is why fasting and skipping meals will only make things worse. In addition to having four to six small meals per day[4] eating healthy snacks will also increase metabolism.[1]
6. Drink water. As with food, depriving your body of water can encourage it to “hoard” rather than “burn”. In order to encourage your liver to focus on metabolism rather than water retention, make sure you drink an appropriate amount of water.
7. Boost metabolism temporarily with aerobic exercise. Different activities burn different quantities of calories, but the important thing is to raise your heart rate and sustain the activity for approximately 30 minutes.
8. Boost metabolism in the long run with weight training. Muscle burns more calories than fat (33 more calories per day, to be exact)[1] so the more muscle you build, the higher your resting metabolic rate (RMR). Every bit of muscle that you gain is like a little factory that burns calories for you 24 hours a day, 7 days a week. This is the only way to increase RMR, which accounts for 60 to 70 percent of the calories you burn daily.[5]

Tips

• There are no “fat-burning” foods. You might’ve heard that certain foods (like celery and grapefruit) increase metabolism, but it’s just a myth.[4] While some foods and drinks like red peppers and green tea have been studied for their potential metabolism-increasing properties, there is no conclusive evidence that whatever influence they have on metabolism is significant enough to result in weight loss.[1]
• Always consult a dietician or doctor before making a major change in your diet and exercise routine.

Warnings

• Expect your metabolism to slow down as you lose weight. The more weight your body is carrying, the more calories your body has to burn in order to sustain itself, even at rest. When you begin restricting your calorie intake, you’ll lose weight relatively easily because your body’s high caloric needs are not being met. But after you begin to shed the weight, the body has less mass to carry and thus needs fewer calories. In order to continue losing weight, you will have to restrict your caloric intake even further in order to maintain a difference between what your body needs and what you are providing.[1] Let’s go through a hypothetical example:
  • You are 200 lbs and your body needs 2500 calories a day to sustain itself.
  • You cut down your caloric intake to 2000 calories.
  • You lose 25 lbs. Now your body only needs 2250 calories to sustain itself because it’s carrying less weight.
  • If you continue with your 2000 calorie per day diet (the diet that helped you lose the first 25 lbs) you will still be losing, but at half the speed. In order to maintain a steady weight loss you will need to reduce your caloric intake further. However, it is at the utmost importance you do not try to consume fewer calories than your RMR!
  • Another possible problem: If you continue with your 2000 calorie per day diet (the diet that helped you lose the first 25 lbs) you may actually gain weight back because of varying levels of exercise. Let’s say you lose 50 lbs. on your 2000 calorie diet. Your sustaining calories might be 1800. You’re actually consuming enough calories to gain weight, but how would that happen if you had stayed to your diet. This can happen when your exercise has burned through many calories. If you slowed on exercise at this point you would actually gain weight again. The point here is to recheck your RMR when you lose weight and compare it to your consumption.

Related wikiHows

• How to Decrease Your Metabolism
• How to Lose Weight Fast
• How to Calculate Your Body Mass Index (BMI)
• How to Gain Weight

Sources and Citations

1. ? 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 http://www.webmd.com/fitness-exercise/guide/make-most-your-metabolism
2. ? http://www.adajournal.org/article/PIIS0002822305001495/abstract
3. ? http://books.google.com/books?id=gRrp3yphhC0C&pg=PT259&lpg=PT259&dq=%2B%22caloric+intake%22+%2Brmr&source=web&ots=En__f5a15l&sig=j7IwWkrMdgfTuDb5Fd27QqWNW14
4. ? 4.0 4.1 http://www.webmd.com/diet/features/rev-up-your-metabolism
5. ? http://www.webmd.com/fitness-exercise/features/jump-start-your-metabolism

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