Why Dieting Below Your Caloric Maintenance Only Works for the Short-term
To lose fat, you must consume fewer calories than your body burns (a caloric deficit). While other factors influence results, this principle is fundamental. However, restricting calories can trigger a metabolic slowdown, a short-term adaptation that becomes problematic long-term.
So what exactly is considered short term vs long term dieting?
Eventually, the body and metabolism will adapt and the person will stop seeing positive changes all together despite how little they are eating or working out. Even worse, they may start to gain weight.
The problem is one of metabolic adaptation: excessive exposure to a given stress—in this case, reduced energy intake - which leads to a slowed metabolic rate.
When you begin to diet and reduce caloric intake, your body taps into energy reserves of stored fat to continue living. Everything from brushing your teeth every morning to sprinting to the bus to get to work on time, all of it requires energy from our stored glycogen reserves. Most of us have quite a bit of that stored as subcutaneous fat.
In the ideal case—at least for the purposes of getting leaner—we’d just keep dieting and keep burning fat. Evolutionary biology tends to run counter to our vanity, however: after a few weeks in a caloric deficit, we stop burning fat.
A full breakdown of the myriad of biological shifts that occur in response to chronic underfeeding is beyond the scope of this writing, but the take home is that your production and secretion of metabolism-regulating hormones generally decrease.
While “starvation mode” isn’t an actual scientific phenomenon, it’s a decent catch-all phrase for what’s really happening.
Put as simply as possible: your metabolic rate slows to match your caloric intake.
Going into a restrictive dieting phase often disrupts the body's overall homeostasis. This includes the metabolism, endocrine system, nervous system and neurological system.
With not enough “fuel”, your body will start to eat away at your muscles for energy rather than digging in to your fat stores. You will trick your body into thinking you're malnourished and you will likely lose muscle over an extended period of time as well as put yourself at risk for hormonal and metabolic damage. Your body will think it needs to store fat for later. This is why some people are often are seen as “skinny fat.”
Enter Reverse Dieting
If you’re someone stuck in a caloric deficit and are unsure what your next move should be, consider reverse dieting. Reverse dieting is the methodological and strategic process of adding calories back into your diet in order to feel better and essentially get your body running at its most optimal level.
When you begin to reverse diet, it's important to keep in mind the primary goal which is not to lose weight or decrease body fat. It’s to strengthen your metabolism while keeping you as close to your current body weight and at the same time increase the amount of food you are consuming. Sometimes, this also includes decreasing the amount of work you are doing in the gym, usually less cardio.
Regardless of the details contingent to the person, reverse dieting is an investment in your long-term health and should be viewed as that rather than a short-term fix. The primary goal with reverse dieting is to fix your metabolism, build muscle, improve strength, develop a healthier and happier body image and improve your relationship with food.