Can You Predict How Much Weight You'll Lose?Mar 11, 2020
Most people have a target weight-loss date — like fitting into a dress for that wedding in three weeks or feeling great in a bikini by the start of summer.
But how realistic is it to hit those marks? How much weight can you lose in a month? Two weeks? Two months? And more importantly, how much weight can you safely lose in a certain amount of time?
Let’s start with the bad news: You can’t predict exactly how much weight you’ll lose in a certain time — there are just too many variables, says Jaime Schehr, RD and naturopathic physician based in New York.
Fitness level, workout intensity, muscle mass, macronutrient intake, sleep quality, stress levels, gender, genetics, medications, and alcohol intake all come into play and influence how much fat your body will both burn and hold onto.
But there’s good news, too: Schehr says you can make a guesstimate of how much weight you can lose in a month, two months, or a year, for example.
How Much Weight Can You Lose in a Month?
A healthy and realistic goal is to lose one to two pounds a week according to the Centers for Disease Control and Prevention. Restricting your calories and/or cutting carbs may help you drop a few more pounds in the beginning (i.e. the first week or so) than you will on average, but this is usually a combination of fat and water.
Based on this, you can estimate a four pound to eight pound weight loss after four weeks of consistently eating a healthy diet and engaging in regular exercise.
How Much Weight Can You Lose in a Week?
You’ll probably hit anywhere from one to three pounds and as mentioned earlier, it will likely be a combination of water and fat. If you lose more than this, you’re probably losing muscle — you want to prevent that as much as possible.
How Much Weight Can You Lose in Two Weeks?
If you were successful the first week and you stay the course, you’ll likely drop another one to two pounds in the second week. The heavier you are, typically the higher your resting metabolic rate (RMR), i.e., how many calories your body burns when you’re sitting still all day.
How Much Weight Can You Lose in Two Months?
As you continue to lose a decent amount of weight (greater than 10 pounds), it’s important to take into account how this affects your metabolism. Recalculate your new RMR based on your new, lighter weight. This should ensure that you’ll continue to lose weight consistently at a healthy rate of one to two pounds a week.
How Much Weight Can You Lose In 4 Months, 6 Months or a Year?
While you’ve been shedding pounds consistently, your metabolism may have slowed because there’s literally less of you that needs to be fueled. What happens at this point in your journey can vary, but some people may hit the dreaded “plateau.” But the good news is that there are a variety of strategies you can try to help you push through it, like eating more (yes!).
To make sure your metabolism remains elevated it’s important to:
- Lose weight gradually
- Include resistance exercises in your workouts
- Eat enough protein to maintain your now-lean body mass
How Many Calories Do You Need to Lose Weight?
How do you determine how much to eat to lose weight? There is a well-established formula to determine your RMR based on age, height, weight, and gender, says Robert Ziltzer, MD, an obesity medicine physician at Scottsdale Weight Loss Center in Arizona. Most online calculators use this formula, making them surprisingly accurate, he says.
Your RMR tells you how many calories you need to eat to maintain your current weight, but when it comes to how many you need to consume to lose weight, it gets a little more complicated.
Experts used to say a 3,500-calorie deficit equaled one pound of fat loss, a concept known as Wishnofsky’s Rule. However, a 2015 study in the Journal of the Academy of Nutrition and Dietetics found this formula has a huge margin of error. This is because it doesn’t take into consideration thermodynamics, which is all the chemical processes that affect how much energy your body burns for fuel.
For more info on this, check out: How Many Calories Does It Take to Lose a Pound?
The researchers added that there are indeed complex, dynamic equations that are more accurate and realistic, but most weight-loss calculators available online (the same ones that work great for determining how you can maintain your weight) don’t leverage these formulas. They are still based on Wishnofsky’s Rule and therefore, are wildly inaccurate, Ziltzer says.
“This [rule] is a simple and easy way to gauge dietary change for consistent weight loss, but, again, there are many other factors that are influential,” Schehr says.
Helpful Weight Loss Tips to Keep In Mind
- It’s important to note that losing a pound of weight is different than losing a pound of fat, Schehr says. The number on the scale could go down due to muscle loss or water weight instead of fat.
- Most people will hit a weight-loss plateau during their journey and need to take additional steps to change up their diet and workout plan to keep dropping pounds, both experts point out.
- The body does have the ability to lose a lot of weight quickly, but it comes at the expense of many vital processes, which means rapid weight loss can be unhealthy, says Schehr.
- If your target number is far from what the scale currently reads, you may want to enlist the assistance of a registered dietitian who can help you with your weight loss journey and take into account all of the variables unique to your individual lifestyle.
The Bottom Line
Everyone’s body (and lifestyle) is different, so you may lose weight faster or slower than someone else and vice versa. Don’t get hung up on timeframes or timelines: Make smart and sustainable food choices, exercise often, and keep your eye on the long game. That way, you can get off the hamster-wheel of “I gotta lose X pounds in Y weeks/months!” and focus on enjoying your healthy life.