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Could Intermittent Fasting Help You Lose Weight?


I’ve long been a critic of fasting for weight loss, because in my experience, lengthy stretches without food can lead to a range of negative side effects, from a lower intake of beneficial nutrients, like antioxidants, protein, and fiber, to fatigue, mood swings, intense cravings, and rebound overeating. But a few recent studies have forced me to reconsider (albeit skeptically) the potential advantages of some forms of fasting. In a previous post, I wrote about a study that looked at nighttime fasting, and now a new study published in Nutrition Journal has examined the benefits of intermittent fasting.

In this study, 54 obese women were randomly assigned to one of two groups. The first followed a low-calorie liquid diet for eight weeks that also required fasting one day a week. The second group of women fasted once a week and adhered to a low-calorie solid food plan for the two-month weight-loss phase. Both groups then transitioned to a two-week maintenance period. 

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The liquid group lost slightly more weight (an average of eight pounds versus the solid food-eating group's average of five) as well as more belly fat, and experienced a greater reduction in both total and “bad” LDL cholesterol levels. The results led the researchers to conclude that this approach (a low cal-liquid diet and intermittent fasting) may be an effective strategy, but I still have reservations.

Throughout my years counseling clients in private practice, I’ve met probably hundreds of people who’ve had success with extreme dieting, including liquid diets, cleanses, fasts, or surgery. But the results didn’t last, and that’s what concerns me. Even if an approach leads to results, if you can’t stick with it, you’re likely to end up right back where you started. That inconsistency can also wreak havoc with your emotions. If falling off the extreme bandwagon causes you to blame yourself, or feel like you failed—again—it can even lead to a sense of helplessness, or wanting to give up all together.

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As a health professional, I want to help my clients improve their health and achieve their weight-loss goals. But I also know that long-term success is a very, very long haul, and mental health is an important part of the equation. So if you’re contemplating intermittent fasting, a liquid diet, both, or any drastic change in your diet or lifestyle, ask yourself if you think you’ll still be doing it six months or six years from now. As I tell my clients, there is no quick fix or overnight tactic that can help you become fluent in a new language or learn how to play a musical instrument, and permanent weight loss is similar—each requires practice, patience, and most of all perseverance!

What’s your take on this topic? Do you think fasting could be part of your daily lifestyle? Please tweet your thoughts to @cynthiasass and @Shape_Magazine!

Cynthia Sass is a registered dietitian with master's degrees in both nutrition science and public health. Frequently seen on national TV, she's a SHAPE contributing editor and nutrition consultant to the New York Rangers and Tampa Bay Rays. Her latest New York Times best seller is S.A.S.S! Yourself Slim: Conquer Cravings, Drop Pounds and Lose Inches.


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