How Long Does it Take to Lose Weight?

A picture of a woman celebrating weight loss success

Success is awesome... but it takes TIME!

People are impatient.

I’m guilty of that myself.

In the modern society, we’ve come to expect quick fix solutions, and are often unwilling to put in the time and effort required to achieve results.

If something is too hard or takes too long, chances are we’ll move on to something else.

Unfortunately, weight loss is one of those things that is both difficult and takes a long time.

How Long Does it Take to Lose Weight?

I get a lot of questions in comments and emails about how long it actually takes to lose body fat.

Many people think they can lose a significant amount of fat in just a few weeks.

This is simply not possible.

To lose fat, one must be in a negative energy balance, and body fat contains a vast amount of energy. A pound of body fat contains 3.500 calories, while a kilogram of body fat has 7.700 calories.

I’m definitely not a fan of calorie counting, because certain changes in food selection often lead to automatic weight loss. However, a calorie deficit is still required to lose weight. The first law of thermodynamics says so.

When you start to eat healthier and start working out, a deficit of 500 to 1000 calories per day is an ambitious goal.

To show you how quickly this may lead to weight loss in the real world, I’m going to do a bit of math.

A Deficit of 500 Calories Per Day

If you have 30 pounds to lose, it will take: (30lbs*3500cal/lbs)/(500cal/day) = 210 days or 7 months.

If you have 100 pounds to lose, it will take: (100*3500cal/lbs)/(500cal/day) = 700 days, or 1 year and 11 months.

A deficit of 500 calories leads to a pound of body fat lost each week.

A Deficit of 1000 Calories Per Day

30 pounds: (30lbs*3500cal/lbs)/(1000cal/day) = 105 days or 3 and a half months.

100 pounds: (100*3500cal/lbs)/(1000cal/day) = 350 days, or 11 and a half months.

A deficit of 1000 calories leads to two pounds of body fat lost each week.

A Simple Formula:

Multiply the amount of weight (in pounds) you want to lose by 3.500, and divide by the calorie deficit you think you’re going to achieve. This is the time (in days) it will take you to lose weight, if you’re very strict on your diet, every day.

This is only a simple estimate, by the way. Your mileage may vary.

Think Months and Years, not Days and Weeks

When you look at those time frames, you start to appreciate how unrealistic quick fix “diets” are for most people.

You also start to understand how incredibly unsuccessful people are going to be if they expect to lose weight in a short amount of time.

The fact is that it can take months and years. The only weight you’re going to lose in a few days or weeks is water weight and a very tiny amount of body fat.

Now there are exceptions to this, of course. There are people who have been able to lose over 100 pounds in a single year, but this is extremely rare.

Then there are others who lose fat much slower than that, despite being very strict to themselves when it comes to eating healthy and exercising.

Don’t Focus on The Scale Too Much

There is a lot more in the body than just fat. There are organs, skin, bones and muscle as well, and muscles tend to grow larger when being pushed to their limits during exercise.

This is why I recommend that people don’t focus on the scale too much. Even if your weight goes down slowly, that doesn’t mean you aren’t losing fat, because you may be gaining muscle instead.

Given how incredibly long this takes, it is really impossible to get a “quick fix”. You must be in it for the long haul, and a lifestyle change is the only permanent way to achieve long term success.

Losing weight is a marathon, not a sprint, and the sooner you accept that, the sooner you will be successful.

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  1. So how do we control hunger? It seem that I must be hungry to maintain and lose weight.

    • Kristjan says:

      Now that’s a tough one.

      I don’t think I can give you any tips that you haven’t read about yourself, as I know you are well informed of these things yourself.

      I find Stephan Guyenet’s articles to be very interesting. Perhaps the only way to lose weight without feeling hungry is to lower your “set point” somehow. Changes in food selection (low carb) can usually get people down to a certain level without hunger, until they reach a plateau.

  2. Great post Kris,

    what I always notice is when people start these ‘quick fix’ diets, or any diet for that matter, the first week or two they will lose a lot of weight and then afterwards the results will slow down and they will lose confidence and eventually give up.

    I think its our culture these days to just expect everything to happen immediately so as soon as something takes a while to work we just get bored/lazy and give up.

    My 2c anyway,


  3. Michelle says:

    This Doctor from SF is amazing. He seems to have so many answers for those of us who are permanently hungry. Wactch everything he has done and a real education in how to eat will be yours.


  4. Kris, I love your note about “Think months and years”. People don’t realize it, but your weight fluctuates ALL THE TIME, depending on hydration, water retention, what you ate that day, and more. So the scale is actually a pretty crappy way to track your weight day-to-day or even week-to-week. I’d suggest throwing out the scale altogether, but a better solution to stop weighing yourself all the time is to keep the scale on the shelf…only bring it down once every few weeks or so. Don’t leave it out where you can step on it all the time.

    • Chris,

      In general I agree, mostly because I don’t think weight is a very important measurement so taking time to measure can be a waste of that time.

      That said, for those who do believe it is important, (and are therefore willing to take the time to do it,) the daily/hourly fluctuations in weight make it overall more accurate to take as many sample measurements as reasonable (weigh daily or possibly even more than once a day?) and track those over time.

      Any individual measurement/sample is usually not very noteworthy by itself, but the trends are.

  5. People always overestimate what can be done in days but underestimate what can be done in months.

  6. Hi kris,
    I only have a 2700 calorie diet and i walk 2 miles 3 times a week and no weight loss since i started 2 months ago. Am i doing something wrong? Also i know about gaining muscle etc. but my pants arnt any looser? Help!

  7. Hi Kris,
    I met your site today, and I must say I am impressed and feel less overwhelmed and defeated.I am a member of sparkpeople and I have been following their recommendations on how to eat.It’s going sort of okay, but I am getting impatient.I’m at a plateau and didn’t know how to move.But now I can try reducing my carbs, whichh i find much easier than reducing fat.
    Q: if I reduce carbs n increase protein and fat.where does the fat go?
    2.If I am taking orlistat, does that mean i have to increase my calories or is it the full-feeling only that counts?
    3.I use the AirClimber and videos for exercise.I was think I could do 2 videos for about 40min instead of one, lift 3lb dumb bells(3times a week), 10,000 steps a days, 1hour walk (relatively slow) much would all these burn?
    I am 231 lbs lost about 7lbs.My goal weight is 132lbs.Do I need to love myself(image) to lose weight? or I can use my future image as my only motivation?
    anxiously awaiting your reply..

    • Hello Izzie.

      1. If you reduce carbs and replace it with protein and fat, you will most likely lose weight. The fat gets burned for energy.

      2. I don’t quite understand what you mean. Orlistat is only mildly effective and personally I think the small benefits are not worth the risks. A low-carb diet is much more powerful.

      3. I don’t know how much these will burn. A combination of strength training and cardio is best. Do NOT exercise too much, 5 times per week for an hour is plenty.

      If you have problems with your body image then eating healthy and exercising can help with that. You’ll feel better and look better. It’s important to do a lifestyle change, short term diets don’t work.

  8. Yaneth Quinonez says:

    My name is Yaneth, I’m 22 years old and a mother of three babies. I have trouble losing weight. I exercise, I eat healthy, I weigh 187 and the least i have gone is 180 but i go back up. What can I do?

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