5 Ways Crash Diets Can Backfire on You

Crash Diets

The reality is that people like quick solutions to problems. That’s why it’s no surprise that crash diets are popular, especially among young people. How many times have you heard someone say they’re trying to lose weight quickly to fit into an outfit for a special event?

But you don’t do your body any favors when you drastically cut calories. Crash diets promise rapid results by severely restricting calorie intake, often to less than 1,200 calories per day. Not only is this approach unhealthy, it’s also unsustainable.

The Illusion of Fast Weight Loss

It’s true that crash dieting can cause the number on the scale to drop fast but you’re not losing all fat. Instead, crash diets cause your body to shed water weight, and muscle mass. If you want a healthy and beautiful body composition, this approach works against you.

How? When you don’t supply your body with enough calories, it goes into starvation mode. Rather than shedding all fat, you break down muscle tissue too. This loss of muscle mass can have profound consequences for your metabolism.

In the famous Minnesota Starvation Experiment conducted during World War II, the thirty-six male participants lost on average 16 kg (about 35 lbs.) within 6 months of semi-starvation. The men took in 1500 calories per day. Muscle mass loss, estimated from measurements of the mid-upper arm and thigh corrected for bone, was 41% of the control value.

Muscle tissue burns more calories than fat tissue, so as you lose muscle, your metabolism slows down. You may like the initial weight loss you get but you’ll see it return quickly once you return to a normal diet. It’s an exercise in futility~

Nutrient Deficiencies and Health Risks

And then there’s the risk of nutrient deficiencies. When you slash calories, it’s harder to get all the vitamins, minerals, and other nutrients your body needs to run chemical reactions and help you feel your best. This can lead to a host of health problems, including fatigue, a weakened immune system, poor concentration, and even organ damage if you take it to the extreme.

Severe or prolonged crash diets can also put a strain on your cardiovascular system, increasing the risk of abnormal heart rhythms or even stroke. Then if you regain it, it can negatively affect your blood pressure, cholesterol, and other heart disease risk factors.

The Binge-Restrict Cycle

Have you ever gone on a very low-calorie diet and experienced overwhelming cravings? When you severely limit your calorie intake, it affects hormones like leptin and ghrelin that control your appetite. You can end up with intense food cravings and a preoccupation with food. You end up fighting with your body to control those heightened hunger signals.

When you give in to these cravings, as you eventually will, and start eating normally, you overeat and regain the weight you’ve lost. You may even overshoot and gain more weight than when you started. This can lead to feelings of guilt, shame, and failure, which can trigger another round of restrictive dieting. This binge-restrict cycle is not only physically unhealthy but also mentally and emotionally damaging.

Metabolic Adaptation and Weight Regain

Repeated cycles of crash dieting and weight regain can also lead to a phenomenon known as metabolic adaptation. When you lose weight, your body adapts by lowering your energy expenditure. This means you burn fewer calories doing the same activities. This adaptation makes it harder to lose weight and easier to regain it in the future.

Research shows people who have a history of yo-yo dieting often have a harder time losing weight and keeping it off in the long term. Their bodies have become more efficient at storing fat and less efficient at burning calories due to repeated cycles of weight loss and regain.

One of the more serious potential health risks of crash dieting is an increased likelihood of developing gallstones. Gallstones are hardened deposits that form inside the gallbladder, a small organ that stores bile produced by the liver. While generally not life-threatening, gallstones can cause extremely painful attacks and may require surgery to remove the gallbladder.

Why does your risk of gallstones go up when you lose weight fast? The odds of developing gallstones on a restrictive diet are related to the rate at which you lose weight. Experts advise losing no more than 1.5 kg (around 3 lbs.) per week to minimize this risk. However, many crash diets encourage people to lose much more than this – often 2-4 kg (5-10 lbs.) per week or more in the beginning.

When you lose weight rapidly, your liver releases more cholesterol into bile and cholesterol-laden bile can trigger gallstones. The gallbladder also contracts less frequently on very low-calorie diets, allowing bile to become overly concentrated and form stones.

A Healthier Approach to Weight Loss

So, if crash diets aren’t the answer, how can you lose weight in a healthy, sustainable manner? Focus on making gradual, sustainable changes to your eating habits and lifestyle. Aim for a modest calorie deficit of 500 calories per day, which should lead to a weight loss of about 0.5-1 kg per week.

Rather than drastically cutting out entire food groups (too extreme), focus on eating a balanced diet that includes a variety of fruits, vegetables, lean proteins, and whole grains. Don’t deprive yourself of an occasional treat either. Combine healthy eating with regular physical activity, aiming for at least 150 minutes of moderate-intensity exercise per week.

Also, address the underlying emotional and psychological factors that may cause you to eat more or crave sugary foods. Develop a positive body image and a healthy relationship with food.


Don’t be fooled by the allure of crash diets. The rapid weight loss you experience mostly comes from water weight loss and muscle mass, not fat. And you run the risk of nutrient deficiencies, increased cardiovascular risks, and a host of other health problems.

Moreover, you could end up in a cycle of restriction and binge eating that is both physically and emotionally damaging. They can slow down your metabolism and make it harder to lose weight in the future due to metabolic adaptation. Aim for slow and steady weight loss through a balanced diet and regular physical activity. And remember, the most important thing is to develop a healthy relationship with food and your body.

With patience, persistence, and self-compassion, you can achieve your weight loss goals in a way that supports your overall health and well-being.


“Gallstones – Symptoms & causes – Mayo Clinic.” 20 Aug. 2021, https://www.mayoclinic.org/diseases-conditions/gallstones/symptoms-causes/syc-20354214.

Ashtary-Larky D, Ghanavati M, Lamuchi-Deli N, Payami SA, Alavi-Rad S, Boustaninejad M, Afrisham R, Abbasnezhad A, Alipour M. Rapid Weight Loss vs. Slow Weight Loss: Which is More Effective on Body Composition and Metabolic Risk Factors? Int J Endocrinol Metab. 2017 May 17;15(3):e13249. doi: 10.5812/ijem.13249. PMID: 29201070; PMCID: PMC5702468.

Montani JP, Viecelli AK, Prévot A, Dulloo AG. Weight cycling during growth and beyond as a risk factor for later cardiovascular diseases: the “repeated overshoot” theory. International Journal of Obesity. 2006;30(S4):S58-S66. doi:https://doi.org/10.1038/sj.ijo.0803520.

Casper RC. Might Starvation-Induced Adaptations in Muscle Mass, Muscle Morphology, and Muscle Function Contribute to the Increased Urge for Movement and to Spontaneous Physical Activity in Anorexia Nervosa? Nutrients. 2020 Jul 10;12(7):2060. doi: 10.3390/nu12072060. PMID: 32664448; PMCID: PMC7400818.

Related Articles:

Is Crash Dieting Harmful to Your Heart?

What is Metabolic Compensation & How Does It Keep You From Losing Weight?

When You Lose Weight, How Much is Fat & How Much Muscle?

Is Your Metabolism “Damaged?”

5 Things That Happen When You Drastically Cut Calories

Metabolic Adaptations – 3 Ways Your Body Tries To Keep You From Losing Weight

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