There is no evidence that slow and gradual weight loss is better.  

Warning: I recommend that you discuss your diet technique with a medical provider.  There is nothing inherently unsafe about intentional rapid weight loss.

For years, I have read book after book, article after article, and watched news story after news story which have reported that the slow weight loss technique is superior to techniques that are fast.  There are lots of diets out there that claim that you can lose a whole lot of weight very fast.  There also diets out there that claim which you should take the slow approach and gradually lose weight through portion control.  In fact, most current guidelines for weight loss recommend gradual weight loss for the treatment of obesity.  This recommendation is indicative of a widely held opinion that weight lost rapidly is more quickly regained. I have always been a person recommends the slow technique to weight loss, but new research has me rethinking my position.

A recent article that was published in Lancet 2014 caught the diet and exercise experts by surprise.  The journal article, entitled “The effect of rate of weight loss on long-term weight management: a randomized controlled trial,” aimed to investigate the effect of the rate of weight loss on the rate of regain in obese people[1].  This finding is contrary to most widely accepted standards and beliefs held by both the nutrition and medical communities.  During the study, researchers performed a randomized interventional trial on 204 subjects in which they had two phases: the weight loss and weight maintenance phases.   If participants lost 12.5% of their weight, they were placed in the second phase to follow their maintenance.  The primary outcome was weight maintenance.  

Of the 200 participants, about half was placed in a gradual weight loss arm, and the other half was placed in a rapid weight loss arm.   After phase 1, 50% participants in the gradual weight loss group and 81% in the rapid weight loss group achieved 12·5% or more weight loss.  At the end of the 144-week phase 2, 71.2% in the gradual diet group and 70.5% in the rapid diet regained most of the weight they had lost in the first phase.  In fact, subject, in both groups, who successfully completed phase 1 lost a little over 30 pounds in the first phase but then gained back all but 9 pounds in the second phase.  The most important supporting element for a rapid weight loss is that a larger percentage of the rapid weight loss arm achieve the desired goal of 12.5% weight loss.  

If you are planning to lose weight, I am not going to advocate that you lose weight quickly based on a single research study.  It is not unsafe to lose weight fast as long as it is intentional and you get enough calories (1200 calories or so per day – less may be appropriate if under the supervision of a medical provider).   You have to pick a diet that works for you, and you can MAINTAIN.  Let me say that again: you need to maintain the changes.   None of the participants in this study keep the healthy habits going, or they would have kept the weight off.  I am not vilifying them, just stating an obvious fact.  If you to make improvements in your diet and exercise habits that you can maintain, it will be easier for you to keep the weight loss.  If you do this half-hearted and your only goal is to fit into an outfit for an event or to look good for an event, you will regain the weight.  A change for lifelong health does not end just because you met the initial goal.  You need to keep pushing for lifelong health.  

I am more concerned about stability.  You shouldn’t worry too much about how fast or slow we lose weight. If you lose it slowly or rapidly, the point is that you lost it and not you have to induce stability.  Stop taking the yo-yo approach and regaining it over and over again.  Faster weight loss can be motivating for some, but for others, smaller changes might be more sustainable. The key is to end with continued stability. If you need to exercise to maintain, don’t stop.  If you need to journal your calorie online, don’t stop.  If you need to weigh yourself every day, step on the scale.  One the weight is off, stop thinking about the weight loss and start focusing on maintenance and stability.  

Warning: I recommend that you discuss your diet technique with a medical provider.  There is nothing inherently unsafe about intentional rapid weight loss.

The bottom line: Gradual weight loss is not superior to rapid weight loss.  More are abel to achieve a weight lsos goal with rapid weight loss.  In this study, the rate of weight loss did not affect the proportion of weight regained within 144 weeks. These findings are not consistent with present dietary guidelines which recommend a gradual over rapid weight loss, based on the belief that rapid weight loss is more quickly regained.  More research is needed, but clearly, you should pick a diet that helps you lose and maintain it which neither of these arms did.