6 Optavia Side Effects to Consider Before Trying the Diet

This diet encourages replacing your regular food with branded supplemental snacks and meals.
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The Medifast diet — which has been replaced by an offshoot program, Optavia — is a weight-loss plan that promises to help you shed pounds easily with its branded snacks and meals. But the reality may look a little different, which is why it's important to be aware of potential Optavia side effects.


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Here's everything you need to know about the side effects of the Optavia diet to help you decide if it's worth trying.


Talk to your doctor before trying this or any weight-loss program to make sure it's safe for you, according to the Mayo Clinic.

What Are Medifast and Optavia?

Medifast was founded in 1981 as a meal replacement weight-loss program that provided pre-made snacks and meals to dieters, according to the company's website.


The company has since phased out Medifast and launched Optavia, so if you're wondering what happened to Medifast shakes, that diet is no more. Optavia instead offers a manifold approach to weight loss, per the website. The program includes:

  • Meal replacements and snacks called Fuelings
  • A "Habits of Health" program that helps you make small behavioral changes to support wellbeing
  • Access to a health and wellness coach
  • Access to other members of the Optavia community


Optavia encourages followers to eat six meals a day, some of which are their Fuelings products and others that are "Lean & Green" meals you make yourself, according to the Optavia website.

The Fuelings snacks (think: shakes, soups, bars and biscuits) are low in carbs and calories, high in protein and contain added probiotics, per the website. The low-calorie "Lean & Green" meal contains lean protein, starchy veggies and beneficial fats, according to the website.


There are three plan options:

  • 5&1 plan:​ Five Fuelings and one "Lean & Green" meal daily
  • 4&2&1 plan:​ Four Fuelings, two "Lean & Green" meals and one snack per day
  • 3&3 plan:​ Three Fuelings and three "Lean & Green" meals each day

What Are the Side Effects of Optavia?

Negative Medifast reviews criticized the diet for red flags like promises of fast weight loss and its extensive use of supplements to replace whole foods, according to the University of Utah Health. And Optavia reviews cite certain side effects that are similar to these Medifast risks.


Here are the possible side effects of the Optavia diet:


Optavia may not be ideal for people with cancer, liver disease, kidney disease, an eating disorder or those who are taking medication for diabetes, high blood pressure, blood clotting or bipolar disorder, according to U.S. News & World Report. If this sounds like you, talk to your doctor before trying this or any diet program.

1. It May Not Provide Adequate Calories

One Optavia diet side effect is that the program may not provide your body with enough calories, according to U.S. News & World Report.

Fuelings snacks are low in calories, typically clocking in around 90 to 120 calories per serving. And "Lean & Green" meals are usually about 300 calories per serving, per the website. Altogether, that can amount to eating as few as 800 to 1,000 calories calories per day, according to U.S News & World Report.


And while this drastic calorie cutting may lead to speedy weight loss, shedding pounds that quickly isn't safe or sustainable (more on why in a moment). Per the Mayo Clinic, losing 1 to 2 pounds per week is the safe, expert-recommended pace of weight loss to aim for in order to give your body the fuel it needs to function at its best.

Though it doesn't specify if these symptoms are due to calorie restriction, according to U.S News & World Report, Optavia side effects may include:


  • Dizziness
  • Fatigue
  • Headaches
  • Loose skin
  • Hair loss
  • Rashes
  • Leg cramps
  • Bad breath
  • Menstrual changes


Calorie intake should not fall below 1,200 per day for people assigned female at birth or 1,500 per day for people assigned male at birth, except under the supervision of a doctor, per Harvard Health Publishing.

2. It May Not Provide Adequate Nutrients

Similarly, another potential Optavia side effect is that not eating enough calories can deprive you of essential nutrients, according to Harvard Health Publishing.


What's more, the diet requires you to replace many — if not the vast majority — of your meals with replacement products (Fuelings). According to the Mayo Clinic, it's almost always better to eat plant-based foods rather than these supplemental snacks, as meal replacements often can't provide the same nutritional benefits as natural foods.

And if you don't get the nutrients you need, there can be health consequences. According to Rush, you can develop vitamin and mineral deficiencies that may cause the following symptoms:

  • Hair loss
  • Burning sensation in your feet or tongue
  • Slow-healing wounds
  • Bone pain
  • Vision problems
  • Irregular heartbeat


Visit your doctor if you show any of these symptoms, as they can help diagnose and treat your nutrient deficiency, according to Rush.

3. It Can Lead to Muscle Burn

Severely cutting calories can not only deprive you of nutrients — it can also lead to muscle loss, according to the Mayo Clinic. That's because your body tends to burn through water weight and lean tissue before fat in response to eating an extremely low-calorie diet.

4. It May Lead to Weight Regain

While Optavia can lead to short-term weight loss, it may not be the best program for keeping those pounds off in the long haul. That's why weight regain is one of the potential long-term side effects of Optavia.

There are a few reasons for this: First, severely cutting calories signals your body to decrease your levels of a hormone that promotes feelings of fullness while also increasing your levels of an appetite-stimulating hormone, per the Cleveland Clinic. In other words, you'll feel hungrier after eating a typical serving, which may encourage eating more than usual and, as a result, weight gain.

Dieting may also negatively affect your metabolism, which can lead to weight regain after a calorie-restrictive diet ends, according to the Cleveland Clinic.


The best way to lose weight safely and sustainably is to eat a diet full of nutritious whole foods, exercise regularly, get good sleep and manage stress, per the Cleveland Clinic.

5. It Can Cause Digestive Problems

Some dieters have reported digestive symptoms like gas, constipation and diarrhea on Medifast or Optavia, according to U.S. News & World Report.

6. It Can Be Costly

While not an Optavia side effect per se, another common complaint is the cost of the program, which can run about $4oo to $450 for three weeks' worth of food, according to U.S. News & World Report. That doesn't include the cost of additional groceries for your homemade "Lean & Green" meals.

Does Medifast Cause Cancer?

There's no evidence to show that this diet is linked to cancer. There are likewise no Medifast diet customer reviews establishing a link between the two.



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