Research shows some people are just born with an innate drive to move more, especially when there’s an abundance of calories available: they perform more Spontaneous Physical Activity (SPA) [Ravussin 1986].
Examples of SPA are:
– Fidgeting (foot/hand tapping, wobbling on feet, etc.)
– Changing posture (on a chair)
– Making gestures when you’re speaking
– Random movements (playing with hair, chewing on pencil, etc.)
More SPA is how their bodies adapt to getting more calories than they really need. It’s an important component of ‘Adaptive Thermogenesis’ (next to changes in resting metabolism), and can range from 138 to 685 calories per day! [Ravussin 1986]
Meaning your annoying friend may be able to eat another half pizza per day without gaining any additional fat.
Other (less fortunate) people seem ‘less adaptive’ to eating more than they need. They don’t become more fidgety, and the extra calories just get stored as body fat [Johanssen 2008].
I’ve created a science-based calculator that lets you estimate how many calories you expend per day, which you can use as a ‘base’ for your bulk or cut.
Then, if you’re very adaptive to calorie intake (highly fidgety), slowly increase (or decrease) your calories and closely watch how your body weight reacts.
For 2 people with the exact same body weight and lifestyle, one could lean-bulk on 4000 calories per day, while the other struggles to keep body fat levels in check at 3200 calories per day, all because of this SPA difference!