How Fast Should You Lose Weight?

by Dr. Ahmed Zayed
Published on May 8, 2019
a bowl of vegetables, weights, and a measuring tape

The weight loss industry is at a rapid growth and has been estimated to reach a global worth of about $278.95 billion by the year 2023 (1). More products are being launched in this industry almost every day, with each company trying to get their cut of this multi-billion dollar industry.

Unfortunately, this leads to many exaggerated claims made by companies – promising the overweight and obese population that they can quickly shed excess weight, while the company is only interested in obtaining the customer’s money.

Quick weight loss programs, fad diets, and weight loss supplements have become a centerpiece of this industry, and millions of customers are falling for the claims made that they can lose a large amount of weight in just a week or two.

While a significant restriction in calories may yield faster weight loss, there are dangers associated with losing weight too fast. Thus, healthy weight loss should be the answer, as well as a longer-term focus on weight loss and weight maintenance, instead of simply focusing on the moment.

Today, we explore this topic by looking at how much weight you should really lose in a week in order to continue supporting your body, while also reducing the excess fat that might be interfering with your ability to keep your body healthy. We will also consider the possible dangers that may develop when you decide to follow programs that might help you lose weight too quickly.

A Safe Amount Of Weight To Lose In A Week

Weight loss is only truly possible when you decide to follow a weight management plan that creates a calorie deficit. What this essentially means is that you should consume fewer calories than the number you would exert on a daily basis. On exercise days, you would increase your calorie consumption for the day. On those days where you will be resting, daily calorie consumption will be reduced as the additional calories will not be burnt through exercise.

The problem here is that some people would follow a program that creates a calorie deficit that is far too significant. The body needs a certain number of calories for survival – when calories are restricted too much, this can lead to potential problems with the body and your health. Even though some diets and programs tend to promise five to ten pounds of weight loss per week, it is generally considered safe to lose less than a total of two pounds each week (2).

This may sound “slow,” but it is a safer approach to losing weight without experiencing significant adverse effects or putting the health and functioning of your body at risk. Two pounds can be lost through a less significant reduction in calorie intake, along with some added physical activity.

At this point, it is important to note that many people may experience a more significant reduction in their total body weight within the very first week that they implement a new diet, along with an exercise plan. This is because water weight is reduced during the initial period when a new weight management program is implemented.

Thus, during the very first week of your program, you might lose over two pounds in total – this is considered normal, but the rate of weight loss will start to slow down during the second week, when water weight has been lost and the time has come to reduce the actual body fat content that you have accumulated.

Why Follow A “Safe” And “Slow” Method Of Weight Loss?

There are many benefits that a person can expect when they follow a program that focuses on safe weight loss instead of opting for a diet that requires a significant restriction on their calorie intake. Additionally, the potential adverse effects that have been associated with dramatic weight loss in a short period will also be avoided – reducing the risks that a person would ultimately impose on their own body if they want to lose weight.

Safe weight loss means taking your time to reduce the excess fat that has accumulated in your body. This is what you may need to do if you truly wish to achieve long-term weight loss. This is because implementing a diet program that will lead to gradual and safe weight loss also means that you will be adopting a healthy diet that focuses on reducing calories only slightly, while also loading your body with essential nutrients.

For weight loss to be possible with this type of program, you will essentially start to eat healthier. You will start to avoid foods that are known to cause fat gain and rather start to eat food that can help to boost your metabolism. This does not only mean unhealthy foods that are high in saturated fats and other compounds known to be harmful to your body will be avoided, but you will also gain more nutrients – this includes good types of proteins, vitamins, minerals, healthy fats, and more.

What Can Happen If You Lose Weight Too Quickly?

Shedding excess weight too quickly can be harmful to your body – unfortunately, most people do not realize this. They only start to realize that losing those excess pounds in a very short period of time can be hazardous to their health once they start to experience the complications that come with this type of weight loss strategy.

First of all, according to the NHS (3), studies have found that when you try to lose weight too quickly, then you are less likely to remain at your new weight after following a caloric restriction diet, compared to losing weight over a longer period of time. This can certainly be unpleasant – you might want to lose weight quickly to attend a wedding, but then afterward you would gain the weight you lost back. This again exposes you to the health risks associated with being overweight or obese – creating a cycle, which will ultimately be unhealthy for you.

In addition to being at risk of gaining back all that weight you initially lost, here is a list of additional risks that you expose your body too when you decide to follow a diet that causes rapid and fast weight loss:

  • In some cases, muscle mass can be lost when following a diet that is exceptionally low in calories. Muscle mass does not only have a factor to play in physical appearance but also helps to keep the body functioning. A study (4) that was conducted in the Netherlands tested the effects of a very low-calorie diet on both body weight and muscle mass. There were 57 participants involved in the study. Some of them follow a standard low-calorie diet, while others were asked to follow a diet that was even more restricted in calories. While the body weight of the participants did decline significantly, the scientists who were involved in the study also found that a significant reduction was observed in lean muscle mass. Those who followed the lowest calorie diet in the group had an alarming reduction in muscle mass – in fact, there was a 600% increase in the loss of muscle mass compared to the other group.
  • When calories are significantly reduced, there is a risk of suffering from nutritional deficiencies. The body needs a certain number of nutrients every day – all cells in the body depend on these nutrients to function and play their part in keeping the body healthy. When nutritional deficiencies develop, the immune system is often one of the first systems within the human body to suffer (5). This means your body will not be able to fight against the disease, as well as infections, as effectively. People with nutritional deficiencies are also likely to experience fatigue frequently. This can start to interfere with their ability to be productive at work and in their day-to-day functions. In addition to a weaker immune system, along with fatigue, hair loss can also occur. Nutritional deficiencies are also likely to lead to bones that are weaker, increasing the risk of fractures and broken bones, even with slight falls.
  • The metabolism may also slow down with a diet that requires caloric intake to be restricted too much. This is one of the main reasons why you would gain weight again once you increase your calorie intake following your diet period. The slower your metabolism, the fewer calories you burn on a day-to-day basis. One study (6) found that reducing calorie intake significantly can lead to long-term complications with metabolism – thus, even when stopping a diet and resuming a normal intake of calories, your metabolism may still suffer the consequences caused by the reduction in your caloric intake. During the calorie restriction period, your metabolism may slow down even more – which means “cheating” will cause a much more significant gain in body weight.

There are other complications that have also been associated with losing weight too quickly. A person who restricts their calories too much is very likely to feel hungry all the time – this, in turn, may lead to binge eating and “cheating” frequently. Combine this factor with the slower metabolism, and suddenly you pave the way for faster weight gain as well.

Furthermore, due to the calorie restriction, you are also more likely to suffer from dehydration. The body consists of a large percentage of water content – when your body gets dehydrated, a number of problems can start to develop and further implicate your overall health.

Dehydration puts you at risk of kidney damage, which can eventually lead to kidney failure. You are also at risk of several serious risks, especially when the dehydration becomes more serious. For example, if you combine your weight loss program with exercise and your body is dehydrated, you are at risk of suffering heat injury. This may, in some cases, even contribute to a possibly life-threatening condition known as heatstroke.

When your body is dehydrated, it also means your electrolyte content is declining. When there are too little electrolytes in your body, you are at risk of complications like seizures. In some cases, a person may even experience a loss of their consciousness if their electrolyte balance becomes too low.

Other complications that are also serious may include cerebral edema, a condition where swelling develops in the brain, as well as hypovolemic shock, which is a shock the body goes into when blood volume declines too much.


Losing weight is surely beneficial for those individuals with excess fat in their bodies, but when weight is lost too quickly, it opens up a doorway to multiple risks and potential dangers. Fast weight loss can lead to malnutrition, along with other potential hazards, that could implicate the general well-being of a person’s body. Thus, it is important not to restrict calories too much and to consider what would be seen as a safe pace of weight loss – in most cases, and this would be a maximum of two pounds every week.



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