Adaptive thermogenesis is very real. It means that as you lose weight your total energy expenditure will decrease. It also means, if you increase food intake your energy expenditure will increase. There is also a lot of inter-individual variability in this phenomenon.
Yet, 85-90% of the change in total energy expenditure comes from changes NEAT or non-exercise activity thermogenesis. When you shed pounds, the body turns down things like fidgeting and skeletal muscle actually becomes more efficient as an adaptation to weight loss.
What a bitch.
Leptin and Thyroid hormone are also going to get a “little” jacked up as a compensation to weight loss.
“Both weight loss and the maintenance of a reduced body weight are associated with small but statistically significant decreases in circulating concentrations of triiodothyronine (T3) and increases in the circulating concentrations of its bioinactive enantiomer reverse T3 (rT3), suggesting that weight loss results in increased peripheral conversion of thyroxine (T4) to rT3…Caloric restriction and maintenance of a reduced body weight are associated with decreased circulating leptin concentrations. Low ambient leptin, in turn, reduces POMC production in hypothalamic neurons. Decreased hypothalmic alpha-MSH (α-MSH), a proteolytic product of POMC, results in decreased activity of hypothalamic pro-thyroid releasing hormone (pro-TRH) neurons”
Yet, as much as we want to blame all this sciencey stuff for why we can’t lose weight and keep it off, it doesn’t actually look to be the case…because weight loss plateaus, especially those within the first year really seem to come down to ONE thing – adherence.
“A reduced energy expenditure in response to weight loss cannot account for an early weight-loss plateaus…In conclusion, the developed models support the hypothesis that an intermittent lack of adherence can lead to an early weight loss plateau.”
-Thomas et al. 2014
Thus, the most prolific reason weight loss halts is due to what Alan Aragon calls – unconscious non-compliance. I call it creeping normalcy.
What can we do to combat this slow slide back to a new normal?
Here are two things!
1. Strength Train
Please for the love of God, don’t just do High Intensity Interval Training. If you want to lose weight and keep it off you need to maintain or even put on lean body mass, and to do that you are going to need to learn how to pick up something heavy three or so times per week.
2. Track Stuff – but don’t be weird.
What gets measured gets managed. Period. Maybe, you track body composition every few months. Is it worth the BODPOD or DEXA fees if it holds you accountable? Probably. I am not a huge fan of people using scales everyday as I have found it promotes weird behavior in most humans, especially females. Therefore, if you hate measuring stuff all the time and it makes you OCD, maybe you just create monthly checkpoints where you pay more attention for 3 to 4 days. You weigh and measure your food and track how many times you “sneak” an extra handful of dark chocolate almonds. Maybe, you splurge and buy a 13 dollar pedometer and keep an eye on your NEAT as best you can. I try to hit 10,000 steps on all non-training days and I really just use this to make sure I am not overly sedentary as most of what I love to do involves me not really moving, other than typing, shuffling my mouse around, and getting up to get a glass of water. I actually find I am even more productive when I take breaks to walk around.