As director of the Nutrition and Weight Management Center at Boston Medical Center, Caroline Apovian is immersed in the science of dieting. Her book The Overnight Diet: The Proven Plan for Fast, Permanent Weight Loss (Grand Central Life & Style, 2013), written with Frances Sharpe, is the culmination of Apovian’s years of research on nutrition, obesity, and diabetes.
According to the School of Medicine professor of medicine and pediatrics, the high-protein, vegetable-rich, “fat-burning” diet can help people lose as many as nine pounds in the first week, while offering an abundance of food options, including chocolate. The diet, which calls for a one-day “smoothie” fast every week, has earned the endorsement of some medical peers, including Louis Aronne, director of the Comprehensive Weight Control Program at New York Presbyterian/Weill Cornell Medical Center, who describes the Overnight Diet as the easy-to-follow, rapid weight loss plan that dieters “are desperately looking for.”
BU Today asked Apovian about what makes this diet unlike the myriad plans preceding it, why protein is so important, and whether it’s really possible to lose weight while sleeping.
BU Today: How is this diet different from the thousands preceding it?
Apovian: This diet combines two approaches for weight loss and does not eliminate any foods. The one-day power-up is based on intermittent fasting and is translated into a day of drinking calories in the form of smoothies, which combine protein and fruits and vegetables; the second method is a protein-rich program to build muscle mass and prevent the shrinking muscle syndrome, plus stay full all day.
How does the Overnight Diet reflect your many years of research and clinical work in the obesity field?
I have done research in methods of weight loss and weight maintenance. We have realized that as you get older, you need more protein, not less—the body loses one percent muscle mass per year after the age of 30. As you lose muscle your metabolic rate decreases and you cannot eat as much as you used to—therefore you gain weight, like most older people do—older than 30 that is.
The plan is being described as “losing weight while you sleep.” Is that accurate?
You need eight hours of sleep per night—if you do not get that, the gut hormones, which produce hunger, are secreted in higher quantities, and you become ravenous. But you can lose two pounds overnight on the power-up first day of the diet. It is mainly water and salt, but you still feel great the next day, and revved up for the rest of the week.
Can you explain the “one-day power-up”?
The power-up day consists of three delicious smoothies and you drink those calories—they fill you up and you get enough protein to feed your muscles. The power-up first day can help you lose two pounds overnight, then the rest of the week you are on the six-day fuel-up with protein, fruits, veggies, and lean carbs.
How important a component of this diet is exercise?
All you need to build muscle and create afterburn, which means your metabolism stays up long after you stop exercising, is 21 minutes, four days per week. The exercises are short bursts of workload and keep your metabolism revved up.
Can you explain the initial loss of so-called water weight and why that happens?
As you eat less carbohydrates and sugars, less insulin is produced by the pancreas. Insulin causes salt and water retention, so less insulin means you diurese, or excrete, all that water and salt.
Isn’t it unhealthy to lose a lot of weight quickly?
The initial weight loss is mainly water and salt, so this is very healthy as long as you keep hydrated for the six-day fuel-up.
How difficult is it to change one’s set point?
Your set point is dictated by your muscle mass–if you build more muscle and keep it from deteriorating, your set point will change for the better.
Who is the best candidate for this diet? Are there people whose obesity is too stubborn for it to work?
Anyone can lose weight on this diet. Fruits, vegetables, and protein in almost limitless quantities can help anyone to lose weight.
When you reach your goal weight on this diet, what is involved in maintaining that weight?
Keep on the same plan of one-day power-up and six-day fuel-up and you will keep the weight off. No foods are off limits.
The diet was criticized by Yale’s David Katz as being “unrealistic,” another fad diet. How do you respond to its dismissal as a fad or just a repackaging of existing diets like the Zone?
Fad? I don’t think so. The Overnight Diet causes weight loss, keeps muscle mass healthy, and prevents muscle loss. This diet was created from the results of scientific research in preventing muscle loss while eating fruits and vegetables to prevent cancer or heart disease. It was created based on the Protein Sparing Modified Fast (PSMF), which was developed in the 1970s and proven to spare lean muscle mass if given to patients who are critically ill in ICU settings. I added fruits and vegetables to PSMF and created a plan that anyone can do in daily life.
How much of this diet’s effectiveness is the result of caloric rather than carbohydrate restriction?
All diets help you lose weight through caloric restriction. It is easier to produce caloric restriction if you eat more protein, which is satiating, and eat less carbohydrate, which is less satiating.
How do muscles communicate with fat?
Muscles, when working, produce irisin, a hormone that can turn white fat into brown fat—brown fat is metabolically active and burns energy. There are more mitochondria in brown fat.
What foods must you give up completely for the diet to be effective?
You do not have to give up any food completely. Of course, I do not consider processed foods and high-sugar processed items food.
Why is this a good diet for older people? Do all older people experience shrinking muscle mass?
As you get older, you need more protein to prevent muscle loss. You also should do resistance exercise to build the muscle up. So this is a great diet for older people, because you calculate your DPR, or daily protein requirement, based on 1.5 grams of protein per kilogram of ideal body weight.
As researchers learn more about genetic predisposition to obesity, is it possible it could be prevented or cured without dieting?
Perhaps, but not in the near future. We will need to change our environment and stop producing processed nonfoods and calling it food. This will take time. We will need to provide people with fresh fruits and vegetables and good protein sources no matter what their socioeconomic status is—right now the cheaper foods are processed and many have sugar as the first or second ingredient. Sugar is an additive that is without fiber or nutrients; it just adds empty calories. Compare that with a piece of fruit, which does have some sugar, but is surrounded by nutrients and fiber. And that piece of fruit can be more expensive than a candy bar right now. We have to reverse this.