In today’s world, where everything from groceries to selfies is just a click away, many of us have started believing that our health, too, can be fixed instantly with the quick-fix weight loss hacks. Juice cleanses and very low-calorie diets are gaining popularity across social media platforms and especially among those wanting to lose weight fast before a wedding, holiday, or big event. But doctors warn that while the number on the scale may go down, your body could be paying a serious price.
“Just like instant shopping or instant uploads, we now live in an age of instant everything, including quick weight-loss options. But behind these fast wins lies a hidden cost, that is your metabolism,” says Dr. Muffazal Lakdawala, Founder of Digestive Health Institute (DHI) and Director at Sir H.N. Reliance Foundation Hospital, Mumbai.
What exactly is a crash diet?
Crash diets are those extreme plans where you eat way too little, sometimes just 800 to 1,200 calories a day. Most of them even cut out whole food groups. You’ve probably heard of things like fruit-only cleanses, the cabbage soup diet, or those week-long juice detoxes. They promise quick results, but the reality is far from healthy.
“The aim is speedy weight loss, not healthy habits,” explains Dr. Lakdawala. “The initial drop on the weighing scale is usually water weight, not fat loss. And this quick-fix attitude often does more harm than good,” he further added.
How crash diets slow down your metabolism
Your metabolism helps your body burn calories and plays a key role in maintaining energy and a healthy weight. It is measured by your Basal Metabolic Rate (BMR), or the number of calories your body burns while at rest.
“When you suddenly cut down too many calories, your body enters what we call ‘starvation mode’ to save energy,” explains Dr. Muffazal Lakdawala. “Instead of burning fat, it begins breaking down muscle for fuel. Since muscle burns more calories than fat, losing it only slows your metabolism further.”
He also warns that crash diets can disturb hunger hormones like ghrelin, which makes you feel hungrier, and leptin, which signals when you’re full. “This is why many people end up bingeing or regaining the weight soon after the diet ends,” he adds.
Over time, a sluggish metabolism can affect more than your waistline, as it can lower immunity and even impact mood and mental well-being.
Warning signs your metabolism has taken a hit
If you’ve tried a crash diet and feel “stuck,” your body may be sending signals. Dr. Lakdawala points to these red flags:
- Persistent tiredness or low energy
- Difficulty losing weight despite eating less
- Feeling unusually cold, especially in the hands and feet
- Hair thinning or brittle nails
- Dry, dull skin
- Digestive issues like bloating, constipation, or irregular bowel movements
How does quick weight loss drain nutrition levels
Beyond metabolism, crash diets often deprive the body of essential nutrients. “These diets usually lack quality protein, healthy fats, complex carbs, and fibre,” Dr. Lakdawala explains. “They also drain reserves of vitamins and minerals like iron, B12, calcium, magnesium, and vitamin D.”
This results in fatigue, hormonal imbalances, irregular periods, weakened immunity, and even bone loss in the longer run.
He adds, “Lack of fibre also reduces gut balance, the very foundation of digestive and metabolic health.”
How crash diets affect your mental health
While the number on the scale might bring short-term satisfaction, the emotional toll of crash dieting can be heavy. “The cycle of restriction and guilt often leads to shame, body dysmorphia, or even depression,” says Dr. Lakdawala. “We see many patients who not only regain the weight but also struggle with a damaged relationship with food.”
What to do instead
The good news is that you don’t need extreme diets to get your metabolism back on track. “Start by fueling your body instead of depriving it,” says Dr. Muffazal Lakdawala. “Eat balanced meals that include all food groups in moderation, focus on good-quality protein, and avoid skipping meals to ‘compensate’ for indulgences,” he further added.
He further shares a few simple lifestyle changes can make a big difference:
- Move daily: Aim for 6,000–8,000 steps, add strength training two to three times a week, or enjoy yoga and dancing.
- Get proper rest: Sleep for 7–8 hours a night and manage stress through journaling, meditation, or breathing exercises.
- Go for regular check-ups: Annual blood tests can help catch thyroid problems, vitamin deficiencies, or insulin resistance early.
- Take care of mental health: If you’re caught in a cycle of crash dieting or emotional eating, reach out to a therapist or a qualified nutritionist.
Dr. Lakdawala says he often sees patients dealing with the aftereffects of crash diets, from constant tiredness and digestive issues to weight that won’t move. “Crash diets may give you quick results, but the long-term damage just isn’t worth it,” he warns.