Quest bars as my dessert?

Most ‘experts’ who recommend limiting carbs at night do so because their assertion is since you will be going to sleep soon, your metabolism will slow down and those carbohydrates will have a greater chance at being stored as fat compared to if they were consumed earlier in the day where they would have a greater probability of being burned. Seems reasonable, but broscience always ‘sounds’ reasonable. These ‘experts’ also often assert that insulin sensitivity is reduced at night, shifting your carb storing directionality towards fat and away from muscle.

Let’s tackle the issue of metabolic rate slowing down at night time first. The logic behind this theory seems reasonable enough: you lie down in a bed and don’t really move, just sleep, so obviously you are burning less calories than if you are awake doing stuff, even if you are just sitting in a chair or couch resting, you have to burn more calories than just sleeping right? At first glance this seems to jive with work from Katoyose et al. which showed that energy expenditure decreased during the first half of sleep approximately 35% (1). However, these researchers did show that during the latter half of sleep energy expenditure significantly increased associated with REM sleep. So, there are rises and falls in sleeping metabolic rate (SMR), but what is the overall effect? Interestingly, at the very least it does not appear that the average overall energy expenditure during sleep is any different than resting metabolic rate (RMR) during the day (2, 3). Additionally, it appears that exercise increases sleeping metabolic rate significantly leading to greater fat oxidation during sleep (4). This seems to be in line with data from Zhang et al. which demonstrated that obese individuals had sleeping metabolic rates lower than their resting metabolic rates, whereas lean individuals had sleeping metabolic rates significantly greater than their resting metabolic rate (3). So unless you are obese, not only does your metabolism NOT slow down during sleep, it actually increases! The idea that you should avoid carbs at night because your metabolism slows down and you won’t ‘burn them off’ definitely doesn’t pass the litmus test.