The world is in the midst of an obesity epidemic, particularly in the U.S., so naturally there’s a corresponding wave of new diets and advice about how to shed those unwanted pounds.
In addition to being overwhelmed by the sheer volume of information, many people are confused about which type of diet to follow. For years we’ve been bombarded with the mantra: eat a well-balanced, low-fat diet. Now we’re hearing the enemy isn’t fat, but carbohydrates.
Eating plans telling you what types of nutrients you should eat and those to avoid, but there are also countless commercial diet plans. Weight Watchers, Atkins, South Beach, Zone, and Jenny Craig are some of the more well known. How does someone sort out which diet is best?
While one study suggests doctors should recommend Jenny Craig and Weight Watchers for their patients who need to lose weight, the truth is, if you’re eating fewer calories — and stick with it — all diets work. Typically, you will lose more weight in the first couple of weeks on any given diet, and weight loss will progress at different rates thereafter depending on the type of diet and the individual.
“We know from research that any diet will help you lose weight. It’s just a matter of cutting calories,” said Joan Salge Blake, MS, RD, LDN, clinical associate professor at Boston University, and spokesperson for the Academy of Nutrition and Dietetics.
It’s simply a matter of numbers. Take in fewer calories by eating less, or combine eating less with moving more, “which is the best combination,” Blake said.
“But the question is, is it a) healthy for the long term and b) can you really sustain it in the lifestyle that you have? And often times the answer is no, no because the weight comes back on,” Blake said. “We have a lot of Americans out there who are experts at losing weight. The issue is keeping the weight off.”
When you’re evaluating which diet to try, consider what is required and whether you can make it part of your permanent lifestyle rather than just a short-term fix.
“The best diet to go on is going to be something that is going to be able to get the weight off and that is enjoyable, tastes good, and allows you to keep eating like this for a very long time,” Blake said.
One of the reasons people fail at diets is they have unrealistic expectations to begin with about how much and how fast they can lose weight.
“Don’t assume that there’s a quick way to get off something that’s been happening for a while. A change in lifestyle . . . got you into this weight predicament and that means a change in lifestyle is going to get you out of this predicament,” Blake said.
You should aim to lose about 10 percent of your body weight over a 6-month period, Blake said. This approach individualizes weight-loss based on your starting weight.
For example, if you weigh 300 pounds and set out to lose 10 percent of your body weight over 6 months you’re going to lose roughly a pound a week. If you weigh 140 pounds and you want to get to 120, losing 10 percent of your body weight over 6 months will only result in a half or a quarter of a pound per week.
“I think what happens is people that want to lose that last 10 or 20 pounds say ‘Gee I want to lose a pound a week. What can I do to get a pound a week off?’ And they do these elimination diets that are very, very stringent (a lot of times they’ll lose just water). They do it thinking they want the fast weight off, and it comes off, but really does it stay off?” Blake questioned.
Usually not, because the diet isn’t sustainable. You lose the weight but then you go back to what you were doing before and it comes right back.
Keep in mind that losing a small amount of weight can be harder than losing more. If someone weighs 300 pounds and wants to lose 150, they’re going to lose weight much more rapidly than someone who is trying to lose 10 to 20 pounds, Blake said.
Someone who weighs 300 pounds is likely consuming between 2,500 and 2,700 calories to maintain that weight. If they cut 500 calories a day, the weight will come off fairly rapidly. But if you weigh 140 and are consuming 2,300 calories to maintain that weight, you don’t have as many calories available to eliminate.
“It’s harder for them to cut back because they’re already eating less,” Blake said.
Another important point to remember: after you lose weight you need fewer calories to maintain that new weight. You must adjust your diet to your new caloric needs.
Quite a bit of evidence indicates low-carb diets are most effective, at least in the short term, but more research is needed. One reason researchers think this is true is because protein causes greater feelings of fullness (satiety) so you naturally eat fewer calories.
In addition, carbohydrates are converted to sugar (glucose), your body’s first choice for fuel. Its second choice is fat. Theoretically, if you’re eating fewer total calories and reduce your intake of carbohydrates, your body will burn stored fat for fuel.
Low-carb diets have also been shown to improve health markers in people with high cholesterol and insulin resistance.
If you go with a diet that isn’t restrictive of carbs, make sure you’re eating the right ones — fresh vegetables, lots of leafy greens, some fruit, and whole grains. Stay away from highly processed carbs — for example, products made with refined sugars and white flour — and highly processed food in general.
So, does it matter what kind of diet you choose? It could if you have a health condition or take certain medications. If that’s the case, talk to your doctor before making any drastic changes in your diet.
Make an appointment with a registered dietitian nutritionist (RDN). It’s likely covered by your insurance, and an RDN can tailor an eating plan to addresses your personal history, your medical history, and what’s going on in your life.
Blake recommends staying away from juice fasts and liquid diets designed to “cleanse.”
“The body doesn’t need a cleaning diet. It can clean itself,” She said. Beyond that, you’re just not giving your body the nutrients it needs, specifically protein.
“Your body needs protein to maintain health and muscle mass, and if you go many, many days without protein, your body is going to start breaking down your lean muscle mass to provide the protein that it needs for other functions in the body,” Blake said.
Lean muscle mass is correlated to your metabolic rate and losing muscle mass slows your metabolism. When you go off the fast your metabolism could be slower than it was before you started.
“. . . You’re not really doing your body any good. And you know, mentally and emotionally you’re not doing any good either because nobody likes to fail,” Blake said.
May 22, 2015
Christopher Nystuen, MD, MBA