The U.S. National Library of Medicine defines rapid weight loss as losing more than 2 pounds per week over several weeks. Typically, rapid weight loss occurs due to a significant reduction in calorie intake. If you look at most fad diets, you’ll see that most are extremely low in calories.
Some people call these “crash diets.” They eat fewer calories with the goal of losing weight quickly. While calorie restriction is often necessary to create the deficit needed for fat loss, going too extreme can cause you to lose weight too quickly.
But if you go too far, rapid weight loss can have a host of short- and long-term consequences, even making your efforts counterproductive.
Short-term effects of rapid weight loss
When you first start losing weight quickly, rapid weight loss can make you think your body is burning fat. In fact, the initial weight loss comes mainly from water and glycogen stores, not fat. As the body depletes its glycogen stores, water is also released, causing weight to drop rapidly.
You may experience negative consequences such as:
- Digestive disorders: constipation, diarrhea, nausea or fatigue often occur when you cut too many calories.
- Weakness and exhaustion: the body’s lack of energy makes it difficult to concentrate and makes you dizzy.
- Gout risk: Sudden weight loss can trigger gout attacks, especially in people at high risk.
- Gallstones: Some studies have shown that rapid weight loss is associated with the risk of gallstones, causing severe abdominal pain or complications of the liver and gallbladder.
So, instead of feeling relieved when seeing weight loss quickly, many people fall into a state of exhaustion and encounter new health problems.
Long-term effects of losing weight too quickly
One of the most common long-term effects of losing weight too quickly is actually gaining weight. Rapid weight loss is difficult to maintain. Studies show that:
- After 2 years, less than half of people who maintain their weight have lost it.
- After 5 years, that number drops to only about 20%.
This shows that rapid weight loss is not only difficult to keep off, but can also easily lead to a “lose-gain-lose-gain” cycle that can be detrimental to both your physical and mental health.
Staying on a very low-calorie diet for long periods of time can also lead to nutritional deficiencies. Your body needs certain nutrients to function optimally. If your diet is so restrictive that you can’t get enough of the nutrients you’re missing, you may end up with deficiencies in the nutrients you’re missing. This can lead to other problems. For example, research has linked iron, copper, and zinc deficiencies to hair loss. Deficiencies can also lead to poorer gut health. Gut health is important for the brain and helps protect against chronic disease.
So, the effects of losing weight too quickly are many and can vary depending on your diet and how long you stick to it.
What is a healthy way to lose weight?
Most experts agree that if you want to lose weight, it is best to lose 0.5 to 1 kg per week. This requires adopting sustainable weight loss strategies that fit into a healthy lifestyle.
Here is a rule of thumb to consider:
1. Eat enough calories to meet nutritional needs
Eat enough calories to meet your nutritional needs: Instead of going on extreme diets, calculate your calorie needs and cut back moderately. Some people have different nutritional needs, so if you are unsure, you can consult a nutritionist. For example, nutritional needs may change during pregnancy or breastfeeding. Or, needs also change depending on life stage, with some pretty significant changes depending on whether the person is a teenager, an adult, or an older adult.
2. A diet that covers a wide range of food groups
One common theme among fast weight loss diets is that many people skip whole foods. This is how nutritional deficiencies can start to form. Your diet should include carbohydrates, proteins, and fats. It’s important to choose healthy versions of each. For example, healthy fat sources include avocados, olive oil, nuts, and seeds. Whole grains and fruits are healthy carbohydrates, while lean meats, fish, and eggs are all healthy protein sources.
3. Prioritize natural foods over processed foods
Some diets consist primarily of prepackaged or processed foods. This means they contain other substances that may not be good for you, even if they are within the dietary guidelines. Fresh vegetables, fruits, and whole foods are always better choices.
4. Develop healthy eating habits
Not taking the time to sit down and enjoy your meal slowly can prevent your body from recognizing when you’ve had enough. Eat slowly, chew thoroughly, and avoid working while eating. These habits will help you recognize when you’re full and avoid overeating. Avoid crash diets: Remember that these diets are temporary. Once you stop, the weight will come back. Instead, focus on building a balanced eating lifestyle that you can maintain long-term.
