Weight Loss on a Low-Carb Diet

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Committing to changing the way you eat takes effort, so it's natural to wonder if your efforts will pay off—and when. The truth about low-carb diets for weight loss is that it's very difficult to predict who will lose weight, how much they will lose, and how long it will take. There are simply too many variables at play.

It's also important to understand that the definition of a low-carbohydrate diet is loose. For some people, it may mean casually cutting back on refined carbs, but for others it might mean reducing total carbohydrate content to a specific goal. Most of the time, low carbohydrate diets provide about 50 grams of carbohydrate per day to a maximum of 150 grams of carbohydrates per day.

While research has shown that people can lose weight on low-carb diets, there is no guarantee that you'll have the same experience. However, most people can expect to lose some weight whenever they make dietary changes like reducing their carbohydrate intake. Understanding the science behind the diet will help you see how and why it works.

Before You Start

Knowing what your body does in response to dietary changes as well as the timeline it follows can inform your weight loss estimates and keep you on the right track as you progress. This general overview indicates what happens during the first month you're committing to a low-carb diet.


Common Mistakes to Avoid When Starting a Low-Carb Diet

Week 1

During the first week, there will be a shift in your body's metabolism. Instead of primarily using carbohydrates for energy, your body will switch to other sources.

If you consume fewer than 50 grams of carbohydrates per day, your body is likely to activate a process called gluconeogenesis where energy is created by breaking down non-carbohdyrate sources (such as certain lactic acids or amino acids). If your body still cannot make enough glucose by gluconeogenesis, your body will begin to make ketone bodies (from stored fat) as an alternative for fuel.

Some weight loss at the outset is normal—but at this stage, you're losing water weight, not fat. This happens because:

  • The glucose stored in our liver for easy use by our body for energy takes the form of a molecule called glycogen.
  • These molecules are bound up with a lot of water.
  • When you first start a low-carb diet, the stored glycogen is released and broken down, along with the water that comes with it.

People who restrict carbohydrate intake to less than 50 grams a day (which is considered a very low-carb diet) typically see a more profound loss at this stage than those who stick to a diet of 60 and 130 grams of carbohydrates daily.

However, since the average American diet contains about 200 to 300 grams of carbohydrates daily, any reduction in carbs is likely to produce a noticeable change. One of the interesting (and sometimes discouraging) things about losing water weight is that once it's gone, it doesn't stay away. If you return to eating a higher level of carbohydrates, you'll increase your glycogen stores, causing water-weight gain virtually overnight.

If you're anxiously tracking lost pounds, these shifts may be troubling for you. Even when you're losing fat, fluctuations in fluid levels can make it look like you're experiencing a stall in weight loss (sometimes referred to as a plateau).

As your body is adjusting, try to avoid becoming too focused on the scale. Remember that weight loss takes time and consistency.

Week 2

After a week of roller-coaster-like metabolic shifts, the second week of a low-carb diet is much more stable. If you respond well to a low-carb diet, this is the point at which most people will begin to experience real fat loss.

If you're not seeing changes, don't despair: Some bodies take a little longer to adjust. Patience is key!

Week two is a good time to check in with your diet and ensure that you're including plenty of healthy carb alternatives to make up for the carbs you've cut out. Many fruits, vegetables, grains, dairy products have carbs, but you'll be getting more fats and proteins, too.

Aim to choose healthy sources of protein and fats (called monounsaturated and polyunsaturated fats) most of the time, including:

  • Avocado
  • Healthy fat-rich fish, like salmon
  • Nuts and seeds
  • Olive oil

Fruits and vegetables will be a staple of your diet, but be sure to focus on low-carb options such as:

Weeks 3 and 4

During the second half of the first month on a low-carb diet, your body will usually begin to settle into a pattern of weight loss. Your weight loss rate depends on many factors, including how much weight you have to lose. People who begin a low-carb diet with less fat to lose generally lose weight more slowly than those who started out with more.

After the first couple of weeks on a low-carb diet, people may lose between 1/2 pound and 2 pounds a week, which is considered a healthy rate.

How should you track your weight loss during this stage? Experts often recommend the following:

  • Be consistent. Choose a consistent time of day to weigh yourself. People often opt to weigh themselves first thing in the morning after going to the bathroom but before eating. These factors make it easy to stick to a routine as well as make the best possible basis for comparison.
  • Consider your cycle. If you are having a menstrual cycle, you may decide not to weigh yourself during the second half of your cycle—especially if you tend to retain water.
  • Limit your weight-ins. The usual advice is to weigh yourself once a week instead of every day. The normal day-to-day weight fluctuations in body weight come from your body's fluid balance, how much fiber you eat, and other factors.

Low-Carb vs. Low-Calorie

You may be surprised to hear that on a low-carb diet, weight loss mainly happens in the same way as with any other weight loss diet. It involves consuming fewer calories than you expend (creating a calorie deficit).

A low-carb diet may reduce your body's desire to eat more which inherently reduces your calories. You can think of it as changing demand rather than the supply of food.

How does this work? Carbohydrate reduction seems to work on the appetite in multiple ways, such as by altering levels of hormones that regulate your body's hunger and satiety signals.

In terms of specific weight loss, some research suggests that people lose approximately the same amount of weight on a low-carb diet as on a low-calorie diet.

A Word From Verywell

If you find a low-carb diet helps you manage your weight and you don't feel deprived of high-carb foods, it may be the right option for you. It's worth noting that some studies have shown low-carb diets may be challenging to stay on for a long period of time.

When you're thinking about changing your eating habits, keep in mind that you're most likely to stick with a diet that includes healthy foods you enjoy as well as produces results. Before beginning any diet, check with your doctor to make sure the plan you're considering is a safe option for you.

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4 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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