Why eating close to bedtime may actually help you lose weight!

by Rich Fahmy

Tis the season of resolutions so I thought a little discussion on a popular weight loss myth would be a nice blog post for January. The myth is one we hear a lot, especially in the form of random advice people start dispensing immediately upon hearing that your resolution is to lose weight. It comes in a few different forms but it usually sounds something like this: “Don’t eat past *insert favorite time here* o’clock because food just sits there in your stomach and turns to fat while you sleep!”

Let’s take a look at this one with a little common sense and a little science and hope we can debunk this one for good!

A little common sense:

First and foremost, digestive and metabolic enzymes don’t wear watches. Science has yet to find an enzyme that at 6:30PM says “Halt!! All calories consumed from here until sunrise will now be shuttled to fat stores!!” And what happens if I’m on a flight from LA to NYC, do I have to stop eating at 3:30? So unless you can convince me of the magical Fat Fairy that flies around at night causing all calories consumed within 3 hours of bedtime to be stored as fat, I’m not buying it.

You may then ask, then why did it work for my office mate or friend? Well very simply, it was an easy way to cut calories. To lose weight, we need to move more and eat less. And if I’m the type of person that normally plows through two servings of Ben & Jerry’s Chunky Monkey at 8PM; and I now suddenly stop because of this myth then it’s not because of the timing, it’s because I removed 600 calories from my day. So it made me eat less automatically, irrespective of time of day.

A little science:

The myth often rests its logic on the idea that we must somehow metabolically shut down so everything we eat just “sits” in our bellies and we don’t do anything with it but store it as fat. The truth is that even though our internal organs only make up about 5-6% of our body’s total mass, they make up for a whopping 60% of our resting metabolic rate. For example, the brain alone burns about 109 calories per pound of its mass per day which means a 3.1 pound brain (or about 1400g, the average for an adult human) would burn about 338 calories a day just on its own! What’s the point here? Most of the energy we expend is expended to keep us alive and functioning and since when we sleep, we need to be alive and functioning too, we don’t necessarily shut down or down regulate vital functions, and these vital functions burn a hefty amount of calories.

If we try to examine actual numbers, available studies reveal that sleeping metabolic rate is about 95-97% that of waking metabolic rate for an equivalent amount of time. That is, if I were to burn 1492 while awake and not doing anything but sitting there and hardly moving for 10 hours, I would burn 1416 calories while asleep for the same 10 hours. That’s not enough of a difference to account for the massive weight gain that people blame on this myth. Remember though this compares sleep to just sitting there awake fairly motionless, so think of it like this: if you surfed the web for 8 hours and slept for 8 hours, the number of calories you burned would be within 3-5% of each other.

So how does the bedtime snack help?

Well, one of our main goals when losing weight is to not be hungry. To put it simply, we overeat when we’re hungry. So appetite control is vital during our battle of the bulge this resolution season. So long as in a 24 hour period, I’ve burned more calories than I’ve consumed, I will lose weight in that same period even if some of those calories came at 9PM. If a little snack closer to bedtime will keep you from waking up at 1AM and taking out one of those familiar white cartons of leftover Chinese food in the fridge, then for Pete’s sake have the snack! It can actually help keep your calorie intake in check.

Happy New Year and here’s to a great 2010!

About the author:

Rich Fahmy M.S. is the Director of Education for Oracle Fitness Education, a company that specializes in online education for health and fitness professionals. His only New Year’s resolution is to not make resolutions, which either makes him a master of irony or a hypocrite. That part is still up for debate.

References:

1. M Elia Organ and tissue contribution to metabolic rate. In: JM Kinney, HN Tucker, eds. Energy Metabolism. Tissue determinants and cellular corollaries. New York: Raven Press, 1992:61-77.

2. L Garby, MS Kurzer, O Lammert, E Nielsen. Energy expenditure during sleep in men and women: evaporative and sensible heat losses. Hum Nutr Clin Nutr 1987; 41(3):225-233.

3. GR Goldberg, AM Prentice, HL Davies, PR Murgatroyd. Overnight and basal metabolic rates in men and women. Eur J Clin Nutr 1988; 42(2):137-144.

4. H Kumahara, M Yoshioka, Y Yoshitake, M Shindo, Y Schutz, H Tanaka. The difference between the basal metabolic rate and the sleeping metabolic rate in Japanese. J Nutr Sci Vitaminol (Tokyo) 2004; 50(6):441-445.

This entry was written by rfahmy, posted on January 10, 2010 at 12:37 am, filed under Fitness, Food, Life is Fitness, Los Angeles, Nutrition and tagged , , , , , , . Leave a comment or view the discussion at the permalink.