Why Can It Be So Hard To Lose Weight Even If You Exercise?
In the most basic sense, weight loss is as simple as the relationship between calories in and calories out, however, the math is not merely addition and subtraction. Scientists are learning that there are far more complexities to weight loss than simply eating less and exercising more, though the same basic tenets remain.
A recent study illustrates some of the potential complexities of understanding why exercising more doesn't necessarily equate to linear weight loss.
Before we get into the study, let's define a few terms:
BMR: Basal Metabolic Rate is the amount of calories your body would burn if you woke up and didn't move out of bed all day. This is the sum of calories burned from basic body functions like heart rate, respiration, etc.
TEF: Thermic effect of food is the amount of calories burned by digesting food. Yes, the simple act of digestion burns calories. Not very many, but it does burn some. (Fun fact: protein burns the most).
NEAT: Non-exercise activity thermogenesis refers to calories burned doing things that wouldn't normally be considered exercise; such as doing dishes, walking at work, taking the dog for a walk etc.
EEE: Exercise energy expenditure is the amount of calories you burn doing any type of daily exercise.
AEE: active energy expenditure is the sum total of NEAT and EEE.
TDEE: Total daily energy expenditure is the total calories burned on a daily basis doing all of these activities.
A new study published this past August looked at data collected on nearly 2000 individuals and assessed TDEE using a process known as double labeled water (double labeled water is an incredibly accurate method of measuring calories burned and is very interesting if you wanted to do a deep dig into it). In short the study found that for the average person, for every 100 calories burned during exercise, your basal metabolic rate will compensate by burning approximately 28 less calories than it normally would.
As an example, lets say your typical BMR is 2000 calories per day and you decide to run and burn 1000 calories, simple math tells us that you likely burn 3000 calories that day. If we use the simple math of 28 less calories for every 100 calories burned through exercise, we arrive at a much lower number of 2,720 calories (BMR 1720 +1000 cals burned during exercise).
Why does this happen? Very simply put, your body needs calories to survive. Your body will lower energy expenditure to compensate for lower calories by restricting your metabolism and energy levels so that it can store energy for possible later use. This was a very useful function several thousand years ago when humans were subjected to long fasting periods and famines, however in today's society where food and calories are available abundantly, it can become a burden.
Other factors that play into this phenomenon are genetic differences between people and ratio of body fat to muscle. Another interesting point to consider (and many endurance athletes will agree) that after long bouts of exercise we are naturally drawn to eating more and many times will eat more calories than we intended to or realized.
What do we recommend at Be Well Chiropractic? It all comes down to your comprehensive lifestyle. Exercise is incredibly important, as well as nutrition, but neither are more important than the other. Vary the types of exercise that you do throughout the year and put just as much focus on improving body composition via strength training, as you focus on calories burned.