Does Weight Loss Get Harder As Body Fat Gets Lower? The Science of Losing that Last 10 Pounds
For the average healthy adult:
The closer you get to zero percent body fat, the harder weight is to lose. The more body fat you have, the easier weight is to lose.
As you lose weight your body attempts to “conserve energy” by slowing down your metabolism and adapting to the changes (be they a new exercise routine or diet). This can be offset somewhat, but generally “that last 10 pounds” is always going to be the hardest to lose from a biological standpoint. Before we get into details, let’s do a quick overview of what fat is and where fat comes from, it’s a lot easier to lose weight if you understand the science behind it.
What Happens When You Stop Eating? This is the real answer, as you can see it generally concurs with our findings.
TIP: As a rule of thumb, don’t let your body fat fall below 3% or so. Zero percent body fat is extremely unhealthy, and you would be risking death. This also happens to be the main scientific answer to the question of why weight gets harder to lose as you become thinner. Your body is hardwired to ensure your survival. Having backup energy (stored as fat) to avoid immediate death and deterioration is a survival mechanism. This makes sense when you consider the relationship between macronutrients, body fat, glucose, glycogen, insulin, and glucagon.
Rule number one of losing body fat is not to buy anything from anybody (and I mean with dollars or sense). Everyone has an angel. Listen, but fact-check. That includes me. Studies are lacking, and pseudoscience is rampant in weight loss discussions. With that said, the presenter of this video is knowledgeable.
What is Fat and Where Does it Originate?
Fat is calories from macronutrients stored as energy dense matter (fat cells). Your body can turn fat into calories easily, expending very little energy in the process. Fat is easy for your body to both create and use.
FACT: Fats are not the same as fat, see the relationship between fat and fats.
How Calories Work With Weight Loss
When you eat calories (energy contained in food), your body stores or uses all the micronutrients (minerals and vitamins) and then stores or uses macronutrients (protein, fat, and carbs) in fat cells as glucose or in your liver and muscles as glycogen.
All calories come from macronutrients without exception. The calories on the label are not the same as calories stored, the calories you store are what is left over after the digestion process has finished, which itself burns calories (with simple sugars and fats being less energy intense to conserve and proteins and fibers being more energy intense).
In simple terms, you can think of it like this: your calories either chill out in a “calorie store” (glycogen stores in non-fat), get used for right now as energy or for organ usage, or get stored as fat (as glucose) for later use.
TIP: Whether or not you store weight or feel hungry is largely the result of insulin and the hormones it triggers. To stop the crazy fat storage from insulin, focus on a low sugar, high bier diet.
TIP: When you lose weight you also lose “lean body mass”, muscle, and other good types of stored energy. By losing weight at a healthy rate you ensure your weight loss comes from the right places.
Why is the Last 10 Pounds Hard to Lose, is it a Mental or Physical Limit?
There are many factors that go into “why fat becomes exponentially harder to lose” as your body fat gets lower. Those factors are both mental and physical, and both proven and not.
Let’s look at all the science, pseudoscience, and logical conclusions related to the topic:
Conservation of Energy and Weight Loss
All systems must conserve and replenish mass-energy to remain a system, as all systems are generally in a state of entropy.
Mass-energy can never be created or destroyed in a closed system, but in an open system like your body the law switches from conservation to the law of entropy.
Your body is in entropy and your biology (brain, genetics, etc) is trying to conserve the mass-energy of your system. This is to say, your biology doesn’t want you to have zero percent body fat… it wants you to store excess energy in your mass (in fat). This can largely be explained by the theory of evolution, it’s simply not useful to be “model skinny” in the wild where one might not eat for days.
A healthy amount of mass-energy dense matter (fat) in your body is useful for preserving your system, but it doesn’t do much for your beach body. If you have extra fat your body lets you use it, if you are getting low on fat your body puts fat burning on lockdown, requires less calories to add more fat, and generally does everything it can (hormonally) to make you store calories. This can be offset somewhat by focusing on eating nutrient rich foods (as your body will react poorly to having a lack of both energy and nutrients).
Conservation of Energy.
Want to get nerdy? Go learn about mass-energy equivalence. All systems tend to have the same core properties (mass, energy, momentum). Systems in motion tend to stay in motion. Thermodynamics is energy usage, moving takes kinetic energy, your body binds energy in fat cells (conserving energy as mass). I could go on. Weight loss IS energy management, and thus weight loss, diet, exercise, and weight gain are all largely based on physics (and the chemistry of hormones and sugars).
Metabolism and Weight Loss
Weight loss may be a matter of calories in versus calories out, but of course this revolves around being able to “burn” calories, and that depends on the rate at which your body “metabolizes” calories (especially calories stored as fat).
As you continue with a diet or exercise routine your body adapts to the new changes. To avoid your body settling into a routine you can shock your body by switching up your routine and employing “cheat days” and “cheat meals”.
If you just keep evenly reducing caloric intake, and stay consistent with exercise, your metabolism will likely react by slowing down.
Basics of Metabolism.
TIP: Metabolism can be divided into two categories. Learn more about “what is metabolism?”
- Catabolism – the breakdown of molecules to obtain energy
- Anabolism – the synthesis of all compounds needed by the cells
TIP: Metabolism matters. In general, 3,500 calories equals about 1 pound of fat. When you start your diet a 3,500 calorie deficit will equate to 1 pound of fat loss (so if you create a 500 calorie deficit each day, you’ll loose a pound a week). However, as your body acclimates to the new routine that number nearly doubles. In 12 months it’ll take roughly 7,000 calorie deficit over time to equate to 1 pound of weight loss. This can be offset somewhat by “switching up your routine” and utilizing “cheat days”. See NIH Body Weight Planner added to USDA SuperTracker food and activity tool.
Mental Sticking Points
The above problems were both physical, but the last 10 pounds is part mental too. As you get closer to your goal you have to strategically kick up exercise and scale back caloric intake as your body adapts to your new shape. Do it too slowly and your body will adapt faster than you can lose weight, do it too quickly and you’ll lose “lean mass” and muscle rather than fat. Losing the last ten takes a different type of commitment from getting to that point.
Water and Weight Loss
The entire weight loss and exercise process is centered around water. Your body needs water for weight gain, weight loss, and survival. It may not be calorie negative, but water can kick up your metabolism. It’s also needed to turn macronutrients into calories, to process micronutrients, and generally to survive as a human. If you aren’t drinking enough water you are unlikely to get down to those single digit body fat numbers.
Cardio + Working Out = Muscle Mass
Muscle increases metabolism. You aren’t going to get rid of that last 10 pounds with diet alone. Dieting without exercising is unhealthy. If you want to lose the last 10 in a healthy way, you must balance cardio, weight bearing exercise, and diet.
TIP: Now that you know why that last 10 pounds is so hard to lose, check out our page on science-based weight loss tips.