What to Know Before Starting a Liquid Diet

Liquid diets are often associated with rapid weight loss or medical necessity, but is sipping your meals really the right choice for you? From doctor-prescribed protocols to juice cleanses, liquid diets come in different forms. Before diving in, here’s what you need to know about how they work, the risks, and whether they’re the right fit for your health goals.

What Is a Liquid Diet?

A liquid diet involves consuming only liquids or foods that turn liquid at room temperature (think broth, ice pops, and smoothies). There are two main types:

1. Medically Prescribed Liquid Diets

   • These diets are typically recommended before or after surgery or medical procedures, or for individuals with health issues that make swallowing or chewing difficult.

   • They can be further divided into:

     • Clear Liquid Diets: Includes clear broth, tea, cranberry juice, Jell-O, and popsicles.

     • Full Liquid Diets: Adds more variety, such as creamy soups, milkshakes, pudding, and drinks like Ensure or Boost.

2. Juice Cleanses

   • These self-imposed liquid diets are typically focused on juices or smoothies and are often marketed as a way to "detox" the body or kickstart weight loss.

What Can You Eat on a Liquid Diet?

The specifics depend on the type of liquid diet you're following:

Clear Liquid Diet

This diet is highly restrictive and includes:

• Clear broth

• Tea

• Cranberry juice (or other clear juices without pulp)

• Popsicles

• Jell-O

Clear liquid diets are generally only recommended for a short period (three to four days, per the U.S. National Library of Medicine) and are often used before medical tests or procedures.

Full Liquid Diet

A full liquid diet allows more variety and includes:

• Everything on a clear liquid diet

• Strained creamy soups

• Milkshakes and ice cream

• Pudding

• Juices with pulp

• Nutritional drinks like Ensure or Boost

This diet may be used as a stepping stone to solid foods or for individuals who have trouble chewing or swallowing.

Juice Cleanses

The contents of juice cleanses vary by plan but typically consist of:

• Freshly pressed juices (often vegetable- or fruit-based)

• Smoothies

• Occasionally, herbal teas

Can Liquid Diets Help With Weight Loss?

Liquid diets especially those that are low-calorie can result in short-term weight loss.

• A study in Obesity Surgery (August 2018) found participants lost 8 to 10 pounds over one to two weeks while on a medically prescribed liquid diet before bariatric surgery.

• Similarly, a Healthcare study (September 2018) noted liquid diets may yield modest weight loss, though they’re challenging to maintain long-term.

However, keep in mind that most of the initial weight loss is often water weight, not fat. Once you return to solid foods, the weight can quickly return.

"Liquid diets and juice cleanses are not a magic bullet," says DJ Blatner, RDN, author of The Superfood Swap. "What you do for a few days will not significantly change your long-term health. It's the habits you maintain over time that matter most."

The Risks of a Liquid Diet

While liquid diets may sound appealing, they can come with potential downsides:

1. Short-Term Discomfort

   • Severe calorie restriction can leave you feeling irritable, fatigued, and unfocused, per the National Centre for Eating Disorders.

2. Electrolyte Imbalance

   • Extreme diets can disrupt the body's electrolyte levels and blood sugar balance, especially in people with diabetes, heart disease, or kidney conditions.

3. Risk for Nutritional Deficiencies

   • Relying on liquids alone can leave gaps in essential nutrients, including fiber, protein, and healthy fats.

4. Triggering Disordered Eating

   • For individuals with a history of eating disorders, restrictive diets can lead to unhealthy behaviors or mindsets around food, Blatner warns.

Should You Try a Liquid Diet?

When It’s Medically Prescribed

If your doctor recommends a liquid diet, it’s safe to follow under their guidance. This is common before or after medical procedures or during recovery from certain conditions.

For Nonmedical Reasons

If you’re considering a liquid diet for weight loss or "detox," proceed with caution. While a short-term cleanse (up to three days) is generally safe for healthy individuals, there are better ways to achieve sustainable results.

Healthier Alternatives for Weight Loss

Instead of relying on a liquid diet, consider a balanced and sustainable approach to weight loss.

• The Mediterranean Diet: A nutrient-rich eating plan focused on whole grains, fruits, vegetables, lean proteins, and healthy fats. This approach is linked to steady weight loss and long-term health benefits, per an April 2018 study in Nutrition & Diabetes.

• A High-Quality Diet: Reducing added sugars and processed foods while increasing whole, fiber-rich foods can support weight loss and improve overall health, per the Healthcare study.

"The weight you lose will be more sustainable, and you're more likely to keep it off in the long run," Blatner says.

The Bottom Line

If your doctor has prescribed a liquid diet, follow their instructions carefully. For nonmedical reasons, liquid diets are unlikely to lead to long-term health benefits or sustainable weight loss. Instead, focus on building balanced eating habits and creating a healthy lifestyle that works for you. Share this article or subscribe to our newsletter for updates.