What the Optavia diet is, what its one randomised trial found, and why an 800-calorie plan is a medical intervention whoever is selling it.
Optavia is a meal-replacement weight-loss programme: five pre-packaged “fuelings” plus one “lean and green” meal you cook, landing at roughly 800 to 1,000 calories a day, with a coach checking in.
Two things have changed since this page was written. The programme has been rebranded as Trilivy, and we have found the randomised trial that the previous version missed while citing a paper from a publisher we could not stand behind.
Key Takeaways
- Optavia is now marketed as Trilivy; the 5 & 1 plan is the Reset 5 & 1 Plan (6).
- Its randomised trial found 5.7% weight loss at 16 weeks versus a self-directed diet (1).
- The same calorie level is used medically, with medicines withdrawn and food reintroduced in steps (2).
- Gallstones formed in 10.9% of people within 16 weeks of rapid weight loss in one study (4).
- By the company’s own account, about 90% of coaches were clients first (6).
What the Programme Is
SaveThe Optimal Weight 5 & 1 plan, now the Reset 5 & 1 Plan, means five fuelings a day plus one meal you prepare: about 5 to 7 ounces of lean protein, around 1.5 cups of non-starchy vegetables, and a serving or two of fat.
Fuelings are shakes, bars, soups, cereals, puddings and savoury snacks. You eat five or six times a day, the total lands around 800 to 1,000 calories, and a coach supports you by phone or message. Later phases reintroduce ordinary food and move you off the products, which under the new branding are called Refine and Renew (6).
The structure is the appeal: almost every decision is made for you. The structure is also the question, because what happens when the boxes stop arriving is the part that decides whether any of it lasts.
What It Costs
Nobody puts this number next to the before-and-after photographs, so here it is, read off the company’s own store in October 2026 (6).
| What you buy | Servings | List price | What that works out to |
|---|---|---|---|
| Reset 5 & 1 Plan Kit | 140 | $480.00, or $384.00 on a first Premier+ autoship order | 140 fuelings at five a day is 28 days, so about $17 a day at the list price |
| Reset 5 & 1 Active Plan Kit | 170 | $541.75, or $433.40 on a first Premier+ autoship order | The higher-activity version of the same plan |
| One box of shake mix | 7 | $24.00 | About $3.43 a serving if you buy boxes rather than a kit |
Two things are easy to miss in those figures. The kit buys the five fuelings and nothing else, so the lean and green meal is your own groceries on top of it. And the discount is a first autoship order, which means the default arrangement is a recurring subscription, not a one-off box.
Whether that is worth it is a budget question rather than a medical one. It still belongs in the decision, because cost is what usually ends these programmes, and stopping is the phase that decides whether the weight stays off.
The Trial the Old Version Missed
The previous version of this page cited a paper from a publisher we are not willing to rely on for health claims. There is a real randomised controlled trial, and it is worth reporting precisely.
One hundred and ninety-eight adults with overweight or obesity were randomised for 16 weeks to the low-calorie 5 & 1 plan with telephone coaching, a reduced-calorie self-guided Medifast plan, or a self-directed reduced-calorie control diet. Completion was high at 92.3%. The 5 & 1 group lost 5.7% of body weight, with significantly greater reductions in fat mass, abdominal fat and waist and hip circumference than control. Weight change correlated with how much of the product people used and how many coaching calls they completed (1).
Three honest qualifications. The trial ran 16 weeks, so it says nothing about a year later. It was carried out by researchers affiliated with the company. And the comparison was against a self-directed diet with no support, which is a low bar: a large part of what is being measured is having structure and someone to report to.
For the wider context, a network meta-analysis of 121 trials across 14 named diet programmes found that by 12 months, weight loss had diminished across all of them and the cardiovascular benefits of every intervention except the Mediterranean diet had essentially disappeared (5).
Why 800 Calories Is a Medical Decision
SaveThis is the section the page most needed, because the calorie level is not unusual in medicine. It is unusual to do it unsupervised.
| Programme | Calories | What supervised delivery looked like | Result |
|---|---|---|---|
| DiRECT, primary care, Scotland and England (2) | 825 to 853 kcal/day formula, 3 to 5 months | Delivered in GP practices, with withdrawal of antidiabetic and antihypertensive medicines, stepped food reintroduction over 2 to 8 weeks, and structured maintenance support | Remission of type 2 diabetes as a co-primary outcome |
| DROPLET, primary care, Oxfordshire (3) | 810 kcal/day total diet replacement for 8 weeks | Weekly behavioural support for 12 weeks, then monthly for 3 months, with food reintroduction and recorded adverse events | −10.7 kg at 12 months vs −3.1 kg with usual care |
| The 5 & 1 plan (1) | Roughly 800 to 1,000 kcal/day | Telephone coaching from a coach who, by the company’s own account, was usually a client first (6) | −5.7% body weight at 16 weeks vs a self-directed control diet |
Look at the middle column. In DiRECT, the trial that achieved remission of type 2 diabetes, the total diet replacement at 825 to 853 kcal a day began with withdrawal of antidiabetic and antihypertensive drugs, because at that intake those medicines can push blood sugar or blood pressure too low. Food was reintroduced over a structured two to eight weeks, and long-term maintenance support followed (2). In DROPLET, adverse events were formally recorded and behavioural support ran weekly for three months (3).
That is what an 800-calorie diet looks like when it is done properly. If you take blood pressure medication, diabetes medication, diuretics or lithium, starting this calorie level without telling your prescriber is the actual risk, and it is a bigger one than any nutrient gap.
The complication nobody mentions
Rapid weight loss causes gallstones, and the numbers are not small.
In a study of 457 people entering a very low calorie programme, everyone was confirmed free of gallstones by ultrasound before starting. Among the 248 rescanned at 16 weeks, 10.9% had developed gallstones. Higher starting BMI, greater BMI loss and higher triglycerides predicted risk, although most cases could not be predicted in advance (4).
Gallstones can cause severe pain and sometimes need surgery (8). This belongs on any page recommending rapid weight loss, and it was not on this one.
About the Coaches
The previous version described the coaches as certified without saying what that certification is.
Here is the company’s own description, from its coaching page: about 90% of coaches were clients first, and a coach is presented as “a real person who’s been through the journey”, someone who listens, asks questions and acts as an accountability partner (6).
That is a fair and useful thing to be. It is not clinical supervision, and the distinction matters most at this calorie level. Coaches are also compensated for the products their clients buy, which is worth knowing when your coach recommends continuing.
Accountability genuinely helps, and the trial found weight change correlated with completing coaching calls (1). Just do not mistake it for medical oversight.
What to Watch For
- Tell your doctor before starting, especially if you take any regular medication (2).
- Gallstones, particularly with a higher starting BMI and faster loss (4, 8).
- Fatigue, irritability, constipation and cold intolerance, common at this intake.
- Muscle loss if protein and resistance training are neglected.
- The regain question. The transition phase is the whole ballgame, and it is where most programmes at this intensity lose people (5).
Who Should Not Do This
Pregnancy and breastfeeding, children and adolescents, anyone with a history of disordered eating, and anyone with kidney disease, liver disease, gallbladder disease or type 1 diabetes, unless a clinician is directly involved. Anyone on insulin or other glucose-lowering medicine needs their doses reviewed before starting, not after (2).
NIDDK’s overview of treatment for overweight and obesity is the right place to see what the supervised options look like, including the ones that do not involve buying a product (7, 9).
If structure appeals but the packaging does not, our calorie deficit guide covers setting a deficit you can hold, the balanced diet guide covers what to eat, and the fibre guide covers staying full on fewer calories without a branded box.
Frequently Asked Questions
Is Optavia still called Optavia?
Not any more. The programme has been rebranded as Trilivy, and the 5 & 1 plan is now the Reset 5 & 1 Plan within a three-phase Reset, Refine and Renew system. The parent company is still Medifast. If you are researching it, that name change is worth knowing.
Does it work?
In the short term, yes. A randomised trial in 198 adults found the 5 & 1 plan with telephone coaching produced 5.7% weight loss at 16 weeks, with greater reductions in fat and waist circumference than a self-directed reduced-calorie diet. The trial ran 16 weeks and was conducted by the company’s own researchers.
Is 800 to 1,000 calories a day safe?
It is a calorie level used in medicine, and that is exactly the point: in the trials that use it, doctors withdraw blood pressure and diabetes medicines beforehand, food is reintroduced in structured steps, and adverse events are recorded. Doing the same calorie level without that oversight is a different proposition.
What are the specific risks?
Gallstones are the one people do not expect. In a study of people losing weight rapidly on a very low calorie diet, 10.9% who were confirmed gallstone-free by ultrasound at the start had developed gallstones by 16 weeks. Fatigue, irritability, constipation and nutrient gaps are the more common complaints.
Are the coaches qualified?
They are not required to be dietitians or clinicians. The company’s own coaching page states that about 90% of coaches were clients first, and describes a coach as someone who has been through the journey rather than a health professional. Support and accountability are genuinely valuable; clinical supervision is a different thing.
Does it put you in ketosis?
Not by design. This is not a ketogenic diet and it is not built around restricting carbohydrate; the fuelings contain carbohydrate, and the restriction doing the work is calories. Some people do produce ketones at 800 to 1,000 calories a day, because that is what happens at that intake on almost any split of macronutrients. The company’s current materials describe the mechanism as Metabolic Synchronization and do not mention ketosis at all (6).
Is it healthy, or not?
That depends on what you are comparing it with, and for how long. For 16 weeks the trial evidence is real and the weight comes off (1). What makes it risky is running a medically supervised calorie level without the supervision: no medication review beforehand, no structured food reintroduction, no recorded adverse events. The gallstone risk is real and rises with faster loss (4, 8). And it ends in a transition phase that decides everything, which is exactly where programmes at this intensity lose people (5).
The Bottom Line
Optavia, now sold as Trilivy, does produce short-term weight loss: 5.7% in 16 weeks in its own randomised trial, better than dieting alone with no support. The thing to weigh is the calorie level. Eight hundred calories a day is a recognised medical intervention, and in the trials that use it, doctors withdraw blood pressure and diabetes medicines first, reintroduce food in structured steps and record adverse events. Buying the same intake in a box with a coach who was a client first is not the same arrangement. Gallstones formed in about one in nine people inside 16 weeks in one rapid-weight-loss study. If you want to do this, do it with your doctor knowing about it.
This article is for informational purposes only and is not a substitute for professional medical advice. Do not start a very low calorie programme without talking to your doctor, particularly if you take medication for blood pressure or diabetes.
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