How to Jump-Start Your Metabolism

Have you been told your metabolism is slow?  Have you heard of different "tricks" for jump-starting your metabolism?  Do they really work?  Are they even true? There really is no such thing as a "slow metabolism" the way most people refer to it with regard to weight. While there are some medical conditions (such as thyroid) that can affect metabolism & weight, these are easily tested for and rectified. Part of the confusion is due to a misunderstanding of metabolism & what people mean when they discuss it. Total Energy Expenditure (TEE) is the total amount of calories you burn in a day. Some people often confuse this with "metabolism" (RMR &/or BMR) but they are not the same. TEE is the sum total of your "metabolism", the thermal effect of food (TEF), activities of daily living (ADL) & physical activity (PA). Basal Metabolic Rate (BMR) is the number of calories you would burn if you did absolutely nothing all day but laid in bed & slept. Resting Metabolic Rate (RMR) is virtually the same thing as BMR & is often used interchangeably. It is slightly different & is how many calories you would burn if you were awake and did nothing but stayed in bed all day & rested. It is slightly higher than BMR as it includes some activity from being awake. There is really little anyone can do to change or "jump-start" their RMR or BMR. Most of your BMR/RMR is driven by your vital organs (heart, brain, lungs, kidney, liver, etc.). It is relative to your total mass so usually the more of you there is (ht &/or wt) the higher it is. The Thermal Effect of Food (TEF) is the number of calories you burn digesting the food you eat. While the macronutrient composition of the diet may affect it slightly, it is safe to estimate it at 10-15% of the calories you consume. Some people mistakenly use TEF to think that eating or eating more will cause them to burn more total calories or raise or "jump-start" their RMR/BMR.  It won't as TEF is separate from RMR/BMR and is always only a small portion of the total calories needed to be ingested to get the effect. So, to burn or "jump-start" your body to burn an extra 300 calories from TEF one would have to eat 3000 more calories. This leaves a net increase of 2700 calories.  Hardly a "jump-start" to net 2700 calories.  Activities of Daily Living (ADL) and/or Physical Activity (PA) is where we have the biggest influence & can make the biggest difference in TEE. So being more active throughout the day & including formal activity &/or exercise is how we can best impact our total energy expenditure. Sometimes we hear of that lucky person who seems to be able to eat all day and stay thin and believe it is because that person has been blessed with a higher metabolism.  While there are some individual variances in metabolism, it turns out that when researchers look at these “lucky” thin people they find they have higher TEE from a higher ADL & higher PA than heavier people.  They have also found that part of this is from what they now call NEAT or Non-Exercise Activity Thermogenesis.  This is not exactly ADL or PA but is defined as little movements throughout the day such as fidgeting, tapping, standing instead of sitting, crossing one legs, etc.  They have found these can add up and can account for upwards of 300 calories a day or more. So, there is little we can do to affect our RMR/BMR. However, there is a lot we can do each day to influence our TEE by increasing our ADL & our PA & what is now being called NEAT. Lastly, we often hear that our metabolisms slow down as we age. While it does somewhat, the majority of this decline is actually not due to a decline in RMR/BMR but to a decline in ADL, PA, & NEAT & also the resulting loss of muscle that accompanies inactivity. Bottom line... Stay Active & Keep Moving! In Health Jeff