3. Coffee or green tea.
The mythical idea here is that specific ingredients in caffeine-containing drinks will stimulate the metabolism. You can find a study here or there that shows a slight increase in BMR following a big dose of caffeine, but the amount of caffeine is more than what is considered moderate (400 milligrams per day) and the “effect” is VERY temporary. You also don’t want to risk the appetite suppressing effect that caffeine sometimes has, which would result in too little food consumed (not good for BMR).
4. Spicy foods.
Rev up your metabolism with cayenne? Those who subscribe to this myth are counting on the compounds capsaicin and dihydrocapsiate to burn baby burn. The many mice studies that examined these ingredients showed some temporary boost in calorie usage – more likely from thermogenesis than changes in metabolic rate. Results of human studies show more of an appetite suppressing effect (maybe because the subjects’ mouths were on fire?) than a metabolism related effect.
5. Don’t eat past a certain time.
One of the most popular diet myths (although not so clear why this diet myth has gotten associated with metabolism). The idea here is that we eat, then burn off what we just ate, then we eat again, then burn that off, etc. So if we eat before going to sleep, where we are clearly not active, how will we burn that off? In order to have a high metabolism, our bodies simply need enough and our bodies want it distributed nicely throughout the day AND night. Your metabolism does not turn off at night, and calories consumed at night won’t change your metabolism or be used differently than calories consumed during the day.
So what can you do to optimize your metabolism, given how unchanging it is? Fuel it with adequate nutrition so that it never feels nervous about whether or not there is a famine (AKA diet) on the horizon. This means starting your day with breakfast and eating every few hours, avoiding ravenous states of hunger, and eating until you are satisfied. Lean body mass uses more energy at rest than body fat, so maintaining lean body mass as we age (lean body mass naturally declines with age) can also optimize BMR.
Meaghan Ormsby, MS, RD is a dietitian who promotes eating well & keeping it real @ Kitchen Toolz