How Fast Should I Be Losing Weight?

AFS Education

Losing weight is not an easy task, and sometimes getting started can be the hardest part. We have become very accustomed instant gratification in life without having to do much work. Starting something with an end goal that’s one or two years down the road can sound absurd, but that’s what it takes to maintain your weight loss long term. Understanding how fast you should be losing weight, and why, is an important step in the right direction.

How do You Lose Fat?

We’ve said it a million times; fat loss comes from a calorie deficit. Calories out MUST exceed calories in. This does not mean you should starve yourself! When starting a weight loss program your calorie deficit should not exceed 1000 calories/day. If you are in a 1000 calorie deficit/day you will lose 2lbs of fat/week. This, ideally, is the fastest rate at which you would lose fat (most people should expect to be closer to 1.5lbs/week).

Losing Weight Too Fast

Lean Mass:

I know it is easy to fall into the “more is better” attitude. But when it comes to weight loss, it’s not the case! If your calorie deficit exceeds 1000 calories for an extended period of time, your body cannot break down energy from fat fast enough. When this happens, protein from your skeletal muscle begins to be metabolized; meaning you are losing lean mass. Since lean mass is the most metabolically active tissue in the body, this will have a negative impact on your metabolism, as well as your long-term ability to keep off previously lost fat.

Reactive Thermogenesis:

Another concern can be a natural adaptation called “reactive thermogenesis”. Our bodies strive for consistency and stability. Our body does not necessarily WANT to lose weight; we lose weight because it is necessary for survival. As we enter a calorie deficit our body will:

1.) Start to break down fat as fuel.

2.) Slowly start to lower its basal metabolic rate in an attempt to counteract the deficit.

This lowering of metabolism is called reactive thermogenesis. It is the only thing that explains why some people living off of <500kcal/day for extended periods of time (maybe even their entire life) are not continually losing weight after a certain point.

If you are in a deficit of 1000 calories or less/day it is safe to say reactive thermogenesis will happen slowly because your body is able to initially utilize fat for energy. When your deficit exceeds 1000 calories/day (with an extremely low calorie diet) your body’s strive-to-survive mechanism will kick in, dropping your metabolism at a relatively quick pace. Eventually, an intake of only 500 calories/day will not produce any more weight loss, but anything greater will cause you to regain and store fat.

What You Can Expect:

Now that you understand the importance of a reasonable calorie deficit, I must also emphasize that not everyone can achieve 2lbs of fat loss/week. If you are someone who naturally burns, for example, 1700 calories/day, a 500 calorie deficit would be more realistic. This would drop your fat loss down to 1lb/week (still a very acceptable rate). For someone looking to lose 50lbs of fat mass, you are not “failing” if this takes almost a year to achieve. It may even take longer because weight loss is never linear. As you get leaner, you start to see smaller and smaller changes because there is simply not as much fat to lose. That, combined with your body’s response of reactive thermogenesis, may cause your weight loss to slow down. But, by no means are you failing! It is a normal response that anyone who has lost a significant amount of weight, at an acceptable rate, has faced.

Take home Message:

Weight loss takes time! Doing it the right way is the only way to ensure lasting results. Set realistic and obtainable goals and don’t expect things to change overnight. If you can come to terms with how long your goals are ACTUALLY going to take, you are taking a very important step in the right direction!