Can Rapid Weight Loss Be Dangerous?

By: moklesur@bringtheshreds
September 13, 2020

Losing weight fast is normal.

However, I’m sure you’ve been told that you’d be happier losing weight at a steady and slower pace.

That’s because several studies show that slow and steady weight loss is more sustainable. Slow weight loss also comes with lesser health risks (1, 2, 3).

However, recent researches have proven than losing weight fast might not differ much from slow weight loss in terms of safety and efficacy (4, 5).

So, should we lose weight fast? Is it worth the trouble? This article examines this in detail.



According to research, losing between one to two pounds weekly is a safe and healthy rate (1, 2, 3).

If you lose more than that, then that’s rapid and you will be at risk of several health problems, including gallstones, loss of muscle, low metabolism, and nutritional deficiency (4, 6, 7, 8).

Most people attempt rapid weight loss by exercising frequently, and by doing the crash diet, or a diet with very low-calorie content – less than 800 calories daily.

Most people prefer losing weight through the low-calorie diet option, compared to exercising (9).

However, if you are just starting on an exercise plan or a diet plan, then you may lose a lot more than 2 pounds within your first week.

Rapid weight loss is normal at this initial period. The weight lost during this time is referred to as water weight.

When you take in lesser calories than your body uses, your body will then start to withdraw from its energy stores. The energy reserve is known as glycogen. The glycogen stored in your body is bound water, and that water is released when your body burns glycogen for fuel (10, 11).

This explains why your weight may drop rapidly during your first week. Once your body depletes its energy reserves, your weight loss should stabilize at 1 – 2 pounds weekly.



That you’ve lost weight doesn’t mean you’ve won the battle. No, you’ve just made it to 50% of the battle. The major challenge is maintaining your new weight.

Many people who adopt a diet plan regain more than 50 percent of their lost weight after 3 or at most 5 years (12, 13, 14).

That is why you are advised to lose weight at a slow pace. Several pieces of research have shown that people who lose weight steadily are more likely to maintain it in the long-term (15, 16, 17).

Also, plans that involve steady weight loss usually encourages healthy eating behaviors, like more consumption of vegetables and fruits, and a reduced intake of sweetened beverages. Such behaviors can keep weight off long-term (18, 19, 20, 21).

However, results from several pieces of research have not found much differences in the effectiveness of slow weight loss and rapid weight loss, even for the long term (4, 5).

In one of these researches, 103 subjects adopted a 12-week rapid weight loss diet plan, while 97 people chose a 36-week slow but steady weight loss diet.

After three years, an average of 70 percent of participants in both groups had regained their lost weight. This implies that both diet were very effective in the end (22).

Although the results from these studies found that losing weight fast was as effective as slow – steady weight loss, it isn’t likely that a person at home would get the same results.

People who lost weight rapidly were supported by doctors and dietitians during the weight maintenance and loss phases. Studies have shown that receiving support from a health professional can boost your chances of maintaining a healthy weight for a long time (23, 24).

Also, dietitians and doctors try to bring the health risks associated with low calorie intake to the barest minimum. These include nutritional deficiencies, loss of muscle, and gallstones.

People who do the low-calorie diet plan on their own have a very high risk of these clinical conditions.

In summary, you are more likely to lose weight and maintain it by losing it slow but steady. With this approach, you can develop healthy eating habits to maintain the healthy weight. Doing this is safer than the fast weight loss thing, especially if you are not supported by a health professional.


What are the risks associated with rapid weight loss?

While rapid weight loss may seem very tempting, it is not recommended in most cases.

Rapid weight loss diets often have a small number of calories and low nutrient content. This may increase your risk of health problems especially if you stay on this diet for many weeks.

Some of the risks associated with rapid weight loss include:

  • Loss of muscle
  • It slows down metabolism
  • It could cause nutritional deficiencies
  • Even gallstones may form


How can you lose weight at a rate that is considered healthy?

  • Increase the amount of protein in your diet
  • Reduce your intake of starches and sugar
  • Eat slowly. Masticating your food well can help you to feel full for a longer duration
  • Drink oolong or green tea. Studies have shown that these cause a 4 – 5 percent increase in body metabolism and also increase fat burning by up to 17 percent.
  • Eat soluble fiber
  • Engage in resistance training.

FREE 28 Day Clean Eating Meal Plan Here

About Louis

Bring The Shreds was founded by Louis Ha. Louis is an online fitness coach and entrepeanuer based in the Bay Area. Read more of OUR STORY

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