James Levine, a scientist at the MAYO clinic in Rochester, MN Has coined a term, “non-exercise activity thermogenesis,” or NEAT, that describes how the smallest of movements we make every day add up to our overall rate of metabolism. It’s true that the working out and other intentional exercise we do enhance our overall metabolism, and we know that more muscle means a higher metabolism. But the single most important factor in determining whether a person is lean or obese seems to be the amount of moving – fidgeting, walking around, filing, cleaning, etc. – that a person does throughout the day. Dr. Levine was quoted in a Mayo Clinic report saying “Our study shows that the calories that people burn in their everyday activities—their NEAT—are far, far more important in obesity than we previously imagined.” 1
Our environment, of course, determines to some extent how much we move around during the day. An office worker will simply have fewer opportunities for non-intentional exercise than, say, a construction worker, or childcare provider. But regardless of their occupation, obese people sit, on average, 150 minutes more each day than lean people, which means they burn 350 fewer calories a day than do lean people.
In obese individuals, there is some evidence that the amount of movement expended during the day may be influenced by biology. 2 It may be that a complex brain mechanisms encourage certain individuals to move around less, contributing to excess weight and obesity. 3 Specifically, it seems that a certain peptide, Orexin A, acts to stimulate spontaneous physical activity. And in a study this year, Dr. Levine demonstrated the effect of a brain chemical that seems to be directly tied to energy expenditure and NEAT. 4 It’s possible that in naturally obese people, this brain chemical works less efficiently, or is less bioavailable. The important thing to know is that obese people don’t necessarily have a problem with motivation. What keeps them sitting still instead of standing or moving isn’t laziness – its biology.
But the fact that biology seems to be a key factor is actually a cause for optimism. Scientists may one day be able to manipulate the NEAT-related chemicals to treat obesity. And, armed with the knowledge that their biology may have dealt them a lower NEAT, obese people can opt to raise their NEAT simply by moving around more in their daily lives.
What’s next? Well, the National Institutes of Health, in order to understand childhood obesity, is doing a follow-up study about NEAT in children. http://clinicalstudies.info.nih.gov/detail/A_2006-CH-0141.html. And Dr. Levine published a study looking at ways to make our homes, schools, and places of work more NEAT-friendly. 5
In the meantime, you can use NEAT as a powerful tool in the fight to lose weight or stay slim. You could burn an extra 350 calories by adding an hour to your daily workout – or you could simply step a little livelier throughout the day. "Unlike running a marathon, NEAT is within the reach of everyone,” Dr. Levine says.
Reference List
1. Mayo Clinic, Rochester MN. Mayo Clinic Discovers a Key to "Low Metabolism" -- and Major Factor in Obesity. Mayo Clinic News . 2006.
Ref Type: Electronic Citation
2. Kotz CM, Levine JA. Role of nonexercise activity thermogenesis (NEAT) in obesity. Minn Med 2005;88(9):54-57.
3. Levine JA, Vander Weg MW, Hill JO, Klesges RC. Non-exercise activity thermogenesis: the crouching tiger hidden dragon of societal weight gain. Arterioscler Thromb Vasc Biol 2006;26(4):729-736.
4. Novak CM, Zhang M, Levine JA. Neuromedin U in the paraventricular and arcuate hypothalamic nuclei increases non-exercise activity thermogenesis. J Neuroendocrinol 2006;18(8):594-601.
5. Levine JA, Vander Weg MW, Hill JO, Klesges RC. Non-exercise activity thermogenesis: the crouching tiger hidden dragon of societal weight gain. Arterioscler Thromb Vasc Biol 2006;26(4):729-736.
