by Barbara Berkeley, MD
I occasionally receive questions by email or through this blog. Recently, reader Dalon Clance submitted the following in response to the blog called "The Magic Pill":
"I want to ask one thing. You state to eat a low carb diet for weight maintenance? I have also read the studies of Professor Hill from the University of Colorado and co-founder of the NWCR. He states that most of the people on the registry eat a low fat diet. I have also come by research that states that after weight loss, the body prefers carb oxidation over fat oxidation. This means, to my untrained brain, that the body prefers to burn carbs and store fat correct? Also, from my reading, it states that insulin is lowered in the body after weight loss. Would this not push fat to be stored as fat and carbs to be burned as fuel? I also wonder why you would push meal replacements? Would not eating a meal be more satisfying to the body than a bar or shake? Sorry, just some questions from a recently new maintainer."
So Dalon, I believe you would like answers to these questions.
- Why do I recommend a low carb diet for maintenance?
- How does the body change after weight loss ?
- Why does the National Weight Control Registry report that most of their maintainers eat a low fat diet?
- Why do I persist in recommending bars and shakes (meal replacements) during maintenance?
Let me begin with my standard disclaimer. The science behind weight loss and weight maintenance is still young, complicated, and incompletely understood. Little is certain. My recommendations owe a lot to clinical experience because what I believe seems to be born out by the patients I have treated. But there is some flexibility between individuals and what works for one might not work as well for another. Seek your own personal formula for success by sampling different ideas.
Question One:
In clinical practice, keeping carbs low appears to be the winning formula. This is most likely because low carb eating discourages insulin production. Insulin is released by carb eating and then..... insulin stores fat. People who have been significantly overweight often have a problem with insulin. They tend to make way too much of it. Their bodies don't respond properly to the insulin that they do make. This problem is not "solved" by weight loss and can easily recur. Once insulin starts pouring forth again, fat reaccumulates. So the simplest way to avoid the regain scenario is to avoid carbs and thus insulin. It's like having a bum knee. It will feel better if you don't run the marathon on it. But it's not "healed". Best way not to start up the problem again? Don't run the marathon. Eating carbs is your marathon and insulin is your bum knee. You do not have to completely avoid all carbohydrates, but a good place to start is by counting 100 grams of carbs per day and keeping your maintenance diet at that level. For gain: cut back. If your weight is stable or declining, considering ramping up slightly. There is a lot more specific info on carbs and types of foods to eat in Refuse to Regain and also in many of these blogs.
Question Two:
Current science suggests that the most important thing to know about your body after weight loss is that it seeks to regain its lost weight. For more on this, see the previous post: The Magic Pill. To my mind, this is the most misunderstood and underestimated part of the weight loss equation. Here's a way to think of it. Your body was built in ancient times. Weight gain was good, weight loss was bad in those days. So your design is to protect any weight you have and to regain that which you lose. Wish it were different? So do I!! But we must accept the reality and work with it, not pretend it doesn't exist!!!! Gaining weight does not trigger any response even if massive (why would it? It would have never been possible to become massively obese in ancient times). Weight loss on the other hand signals the body to the presence of famine and starvation. You may be happy to lose weight, but your body is not. You may think you were on the South Beach Diet, but your body thinks your tribe experienced a famine. Regaining weight was what would allow ancient people to survive after bad times. Your DNA line has survived into the 21st century for a reason. You are good at survival. Which means you are amply supplied with multiple intense mechanisms to make sure you put that weight back on. UNLESS, you are aware and intervene. Constantly, consistently, and intelligently.
Question Three:
The National Weight Control Registry is a study of maintainers who have lost at least 30 pounds and have kept that weight off for at least a year. The Registry follows many thousands of maintainers. Most participants report eating a low fat diet, but if you look at the way most successful maintainers eat, they also limit carbs very significantly. In Refuse to Regain I document the daily intake described by some maintainers in People Magazine's " Half Their Size" issue. While the maintainers might describe their diets as low fat, they are also very low carb. I believe that it is the carb restriction that is primary in their success, but also that low fat eating helps by cutting available calories. The Primarian Diet that I recommend in my book and in my practice is composed of lower fat proteins and dairy as well as low carb consumption. Lower fat and lower carb are not mutually exclusive and work together well. It is also important to note that low fat and high carb diets are often a recipe for weight gain. I experienced this in my own family when one of my relatives faithfully followed a zero fat diet for many years but ate large amounts of bread, pasta, rice, beans and other sugars and starches and developed significant weight gain. In the face of carb consumption, low fat does not guarantee low weight.
Question Four:
It is certainly best to eat natural foods and foods without additives when possible. On the other hand, my primary goal for maintainers is that they avoid weight regain. Actual food is stimulatory in a way that bars and shakes are often not. It is surprising how difficult it is to stop eating when you try to just eat food on a plate. A number of studies have shown that meal replacement with liquid supplements or bars is an effective tool and we have indeed seen this in practice. Don't underestimate the power of food and appetite. If you eat things that are not self-limited in portion size, you will find that the body's imperative to regain weight quickly takes over. Before you know it, you are eating a whole ton of healthy food, which leads to a whole ton of unhealthy food quite rapidly. I am not a diet purist--something that I take criticism for on this blog regularly. But that is me. I think that staying at healthy weight trumps avoidance of fake sugars, bars, shakes and other aids that make success possible. Seek the combination that works best for you.