How Long will it take to Lose 40 Pounds on a 1,200 Calorie Diet

If you eat 500 calories less than your body needs every day for a week, you'll lose about one pound because 500 calories x 7 days = 3,500 calories.

By: Emily Morse, Published on: 2023-11-03, Last Updated: 03-07-24

Reviewed by: Gretchen Reynolds

Table of Contents


Losing weight is a goal for many people. They often ask, "How long will it take to lose a certain amount of weight?" One common approach is using a 1,200 calorie diet. But before diving into the details, it's crucial to understand some basics. What does a "calorie" mean? Why is "1,200" an essential number for some dieters? In this guide, we'll explore these questions and more. We'll explain how counting calories can help with weight loss and estimate how long it might take to lose 40 pounds on a 1,200 calorie diet.

What is a Calorie Deficit?

Every day, our bodies need energy to function. This energy comes from the food we eat. The amount of energy a food can provide is measured in units called "calories." When we eat more calories than our body uses, the extra calories are stored as fat. On the other hand, when we eat fewer calories than our body needs, our body burns the stored fat for energy. This is called a "calorie deficit." It's like saving money. If you spend more than you earn, you'll be in debt. But if you spend less than you earn, you'll save money. In the case of our bodies, creating a calorie deficit helps us "save" by losing weight.

How does a Calorie Deficit Work for Weight Loss?

Think of it this way: if you have a piggy bank and you take out more money than you put in, eventually, the bank will be empty. Similarly, if our body keeps using more calories than we give it through food, it'll start using up the stored fat.

It's believed that 3,500 calories equal about one pound of fat. So, to lose one pound, you'd need a total calorie deficit of 3,500 calories. This can be spread over a week or even a month. For example, if you eat 500 calories less than your body needs every day for a week, you'll lose about one pound because 500 calories x 7 days = 3,500 calories.

What is a 1,200 Calorie Diet?

A 1,200-calorie diet means that in one day, you eat only 1,200 calories. This number is often suggested for women who want to lose weight, but it's important to remember that everyone's body is different. Some people might need more calories to stay healthy, while others might need less. That's why you have to check your calories with an online TDEE calculator on a regular basis to stay fit and on track. The key is to find a balance where you're eating enough to get the nutrients you need but still creating that calorie deficit to lose weight.

How Long Will It Take to Lose 40 Pounds on a 1,200 Calorie Diet?

1. Calculating your calorie needs

Before starting any diet, it's a good idea to figure out how many calories your body needs each day. This is called your Total Daily Energy Expenditure (TDEE). It includes calories you burn by just being alive, doing daily activities, and exercising. There are many online calculators that can help you find your TDEE.

For example, let's say your TDEE is 2,000 calories. If you eat 1,200 calories a day, that's an 800-calorie deficit each day.

2. Creating a Calorie Deficit

To lose one pound, you need a deficit of about 3,500 calories, as we learned earlier. If you have an 800-calorie deficit every day, it will take a little over 4 days to lose one pound (3,500 ÷ 800 = 4.375).

Now, for 40 pounds:

  • 4.375 days x 40 = 175 days

So, if everything stays the same, and you eat 1,200 calories every day, it will take roughly 175 days, or almost 6 months, to lose 40 pounds.

Factors that Can Affect your Weight Loss Rate

Remember, weight loss isn't always a straight path. Many factors can change how fast or slow you lose weight:

  • Metabolism: Some people burn calories faster than others.
  • Activity Level: If you start exercising more, you'll burn more calories.
  • Age: As we get older, our metabolism can slow down.
  • Health Conditions: Some medical conditions can affect weight loss.
  • Diet: Not all calories are the same. Eating healthier foods can help weight loss.

Tips for Losing Weight on a 1,200 Calorie Diet

Here are some tips you need to follow to lose weight:

1. Eating healthy foods

Even if you're eating only 1,200 calories, make sure those calories are full of nutrients. Go for whole foods like fruits, vegetables, lean proteins, and whole grains. These will make you feel full and give your body the vitamins it needs.

2. Getting Regular Exercise

Exercise can help you burn more calories and speed up your weight loss. It's also good for your heart and muscles. Even simple activities, like walking or dancing, can make a difference.

3. Listening to Your Body

It's important to pay attention to how you feel. If you're too tired or hungry, it might be a sign that you need to eat a little more or change what you're eating.

4. Being Patient

Weight loss takes time. Some days or weeks, you might lose more, and some days, you might not lose any weight at all. That's okay. The key is to stay consistent and keep trying.


Losing weight is a journey, and everyone's path is different. By understanding how calories work and making smart choices, you can reach your weight loss goals. Remember, it's not just about the number on the scale but also about being healthy and feeling good.

External Link: