How Much Weight You Can Lose on a Low-Carb Diet

Committing to a change in the way you eat takes effort, so it's natural to wonder just how much weight you can lose on a low-carb diet before you start one. The truth is, that is difficult to definitively predict, as there are simply too many variables at play. While you can't consider weight loss experienced by participants in studies on low-carb dieting a guarantee of what will happen for you, a couple of pounds a week is reasonable. Delving into the science behind this diet can help you understand when that will start—and why.

What You Can Expect

Knowing what your body does in response to this change in eating, the timeline it follows in doing so, and estimations about the possible number of pounds lost can help you feel more comfortable that you are on the right track. Here's a general overview of month 1:

Week 1

The first week leads to a shift in the body's metabolism. Instead of primarily using glucose for energy, the body must switch to using primarily fat.

Some weight will be lost—but it's water loss, not fat loss. This is because the glucose that's stored for easy use in our liver is in a molecule called glycogen, which is bound up with a lot of water. When starting a low-carb diet, stored glycogen is released and broken down, and water is lost with it.

The weight loss tends to be more pronounced in people who restrict their carbohydrates to less than 50 grams a day (what's considered a very low-carb diet), as opposed to those who stick to a low-carb diet that's between 60 and 130 grams of carbohydrates daily. A standard diet contains about 200 to 300 grams of carbohydrates daily, so a low-carb diet offers a dramatic drop.

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 return to eating a lot more carbohydrates, glycogen stores gradually build back up, with the glucose mainly being processed from protein (a.k.a. gluconeogenesis). This isn't a bad thing at all, as the body needs to maintain a certain level of blood glucose, and having a reserve is important.

However, these changes can be concerning to scale-watchers who are anxiously tracking lost pounds. Even when you're losing fat, the fluid shifts occurring in your body may create what looks like stalls in your weight loss. The trick is not to get too tied to the scale during this time.

Week 2

It's good to think of the second week of a low-carb diet as a week of stability after the roller-coaster metabolism shift. Even so, this is often where the real fat loss will start in most people who respond well to low-carb diets. Some bodies take a little longer to adjust, however, so try to remain patient. 

It's also important at this time to be sure that you're not only reducing your intake of carbs but choosing healthy carbohydrate alternatives as well. For instance, since carbohydrates are found in many fruits, vegetables, grains, dairy products, and alcoholic drinks, you'll be eating more fats and proteins.

You'll want to choose healthy sources of protein and fats (called monounsaturated and polyunsaturated fats) like:

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

Fruits and vegetables are healthy, of course, but you need to choose low-carb options like: 

  • Broccoli and cauliflower
  • Spinach and kale
  • Bell peppers 
  • Brussels sprouts
  • Asparagus
  • Melons like cantaloupe and watermelon
  • Strawberries

Weeks 3 and 4

Sometime in the second half of the first month of your low-carb diet, your body will probably settle into a pattern of weight loss. The rate at which you lose depends on many factors, the most prominent of which is how overweight you are to start. In other words, people with less to lose will lose much more slowly than those with a lot of extra fat.

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 because of day-to-day weight fluctuations due to fluid, fiber consumed, and other factors. Also, women who are having menstrual cycles sometimes decide not to weigh themselves during the second half of their cycles, especially if they tend to retain water at this time.

It's important to choose a consistent time of day to weigh yourself. Most of the time, people choose to weigh first thing in the morning, before beginning to eat and drink, because this is the best basis for comparison. If you weigh yourself at another time of day, there will be more fluctuations.

Continued Weight Loss and Keeping it Off

In a large review study of over 1,000 obese people who followed a low-carb diet, the average weight loss was about 15 pounds for those followed between three and six months after starting the diet. After two years of follow-up, the average weight loss was about 10 pounds. So while there was still a reduction, this data suggests that people do tend to gain back some weight. The review concluded that a low-carb/high-protein diet may be more effective than a low-fat diet 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—by you consuming fewer calories than you expend (that is, creating a calorie deficit).

The difference is that while a low-calorie diet has an externally imposed calorie limit, a low-carb diet works with your body so that you desire fewer calories. It's like changing the demand rather than the supply of food. Carbohydrate reduction seems to work on the appetite in multiple ways, including altering levels of hormones and other transmitters of information about hunger and satiety in your body.

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 can control your weight with a low-carb diet and don't seem to miss carb-laden foods like bread, rice, and pasta, this diet may be a sensible option for you. It's worth noting, though, that studies suggest that the diet may be challenging to adhere to for a long time. It's best to choose a way of eating that's healthy and includes food you enjoy, so you'll be more likely to stick with it. Before starting a diet, check with your doctor to be sure it's a safe plan for you.

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