Weight Loss on a Low-Carb Diet

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. While many studies have shown people can lose weight on low-carb diets, the weight loss experienced by participants in studies on low-carb dieting isn't necessarily what you'll experience.

That being said, most people can expect to lose some weight whenever they make dietary changes such as reducing their carb intake. Armed with the science behind the diet, you'll be able to better understand 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.

Week 1

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

Some weight loss at the outset is normal—but at this stage, you're losing water, not fat. 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 definitely increase your glycogen stores, causing water-weight gain virtually overnight.

Even if you don't start eating more carbohydrates, your body's glycogen stores gradually build back up. This replacement glucose is now being processed from protein (a.k.a. gluconeogenesis) rather than carbs. This switch is necessary, as your body needs to maintain a certain level of blood glucose as well as reserve stores.

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.

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

Fruits and vegetables will be a stable 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. The rate at which you lose weight will depend on many factors, the most prominent of which 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 half a pound and two pounds a week, which is considered a healthy rate.

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. 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.

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.

Continued Weight Loss

A large 2012 review study found that the average weight loss of over 1,000 obese people who followed a low-carb diet was about 15 pounds after three to six months.

At a two-year follow-up, the average weight loss had leveled at about 10 pounds. While there was still a reduction, this data suggests people do tend to gain back some of the weight they initially lose on a low-carb diet.

The review concluded that low-carb/high-protein diets may be more effective than low-fat diets at six months and at least as effective at one year.

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: consuming fewer calories than you expend (creating a calorie deficit).

While a low-calorie diet has an externally imposed calorie limit, a low-carb diet reduces your body's desire for calories. You can think of it as changing demand rather than the supply of food.

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, even though they're not told to limit the amount of food they eat (just the amount of carbohydrates).

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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Article Sources

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