If anyone knows how difficult it is to lose weight and keep it off, it's me. My struggle took off as soon as soon as I entered adulthood. At 18, in my last year of high school, I moved to Italy. In six months, in a town near the Adriatic sea, I managed to put on 25 pounds.
The reason for my Italian waist expansion was clear: I ate ice cream, bread, and mozzarella di bufala like I'd never see it again. Before school, it was not uncommon to stop at a cafe and gossip over cappuccinos and bomboloni — custard-filed donuts. After school, gelato. Dinner usually featured plates of pasta, cheese, and bread. Who needed vegetables when you had fresh mozzarella?
The stay in Italy was delicious. I made friends. I learned the language. I studied the streets, squares, and galleries of Rome and Florence. I also got fat. It took about three years to return to my pre-Italian sojourn size. And keeping the weight off since then has required daily thought and effort: avoiding sugary drinks and late meals, preparing food at home whenever I can, keeping running calorie counts in my head or iPhone app, and regularly weighing myself. When the number on the scale goes up, I try to figure out where I'm going wrong and re-focus. I don't view these efforts with disdain; I accept that they're a necessary part of staying healthy.
I did more than 20 interviews with leading nutrition researchers. I distilled what they told me, for you.
It is with this context that I give you what I hope is a helpful guide to thinking about weight loss. Again, I know how difficult it is to manage one's weight, and how annoying it is to see articles about "10 tricks" that will help bust your belly fat or promises about magic diet-pills and potions. I know from personal experience that there are none, and I wanted to offer you an alternative, something that actually reflects clinical experience and what science tells us about keeping healthy.
I conducted more than 20 interviews with leading diet and nutrition researchers, registered dietitians, physicians, and evidence-based thinkers on weight loss from across North America. Together, they've written or reviewed hundreds of studies and treated thousands of patients. I asked them pretty basic questions: based on the best-available evidence, what advice do you have for people who struggle with their weight? What do your patients who lose weight and keep it off have in common? Where do people go wrong? I distilled what they told me, for you.
The experts I spoke to all emphasized that science has now shown us, pretty much unequivocally, that all diets — low fat, low carb, Weight Watchers, Atkins, etc. — have the same modest results in the long run, no matter their macronutrient composition.
Consider the findings of Dr. Mark Eisenberg, who looked at the research on the South Beach, Atkins, Weight Watchers, and Zone diets for his recent review. He and his co-authors found that no matter the diet, people tended to lose about five to seven pounds in a year, eventually regaining some of that weight later.
This latest bit of research follows other large-scale studies that have come to the same conclusion. This randomized trial involved 300 women on either low-carb, high-carb, or low-fat diets. The researchers found that, while women on a low-carb diet (specifically Atkins) lost a little more, weight loss through this diet was "likely to be at least as large as for any other dietary pattern." In other words, there was no "best diet."
Instead of studying the effectiveness of one diet over another, the researchers I spoke to said they were moving toward trying to understand better how individuals — with their varied personalities, preferences, and genetic makeups — respond to different lifestyle changes. The future is in figuring out more tailored alternatives to the current one-size-fits-all approach, they said.
Until we have that answer, the findings from the literature should be liberating: they mean that we’ve been sold this idea that if we just buy into one particular diet, we will walk the path to thinness. But science (and experience) have shown us that that's not true. You can save your money, and tune out fad diets that will inevitably come in and out of fashion. There's no need to wedge your habits and preferences into an unreasonable or unsustainable diet plan that time has shown will fail. Instead, the experts suggested cutting calories in a way that you like and can sustain, and focusing on eating more healthfully.
As a guiding principle, Dr. Arya Sharma, director of the Canadian Obesity Network, simply tells patients, "The first thing you want to do is eat regularly. If you're starving, you're not going to make sensible choices." That doesn't mean snacking all the time, he added, but just making sure you don't arrive at your next meal hungry. Then, he tells patients to eat more fruits and vegetables, and fewer "empty calorie foods" such sugary drinks and processed snacks.
That's similar to the approach Matt Fitzgerald, author of the book Diet Cults, takes. He told me he ranks foods on an evidence-based quality hierarchy, from more healthy to less healthy:
Eat more of the foods at the top, and fewer as you run down the list.
If you need an even simpler guide, there's the "half-plate rule": make sure half of your lunch and dinner plates are composed of vegetables and fruits; the other half, protein and starch. These are reasonable approaches to eating more filling and fibrous foods that aren't calorie dense — which is what everyone I spoke to recommended.
Some of the best research on what works for weight loss comes from the National Weight Control Registry, a study that has parsed the traits, habits, and behaviors of adults who have lost at least 30 pounds and kept it off for a minimum of one year. They currently have more than 10,000 members enrolled in the study, and these folks respond to annual questionnaires about how they've managed to keep their weight down.
The researchers behind the study found that people who have had success losing weight share a few things in common: they weigh themselves at least once a week. They exercise regularly at varying degrees of intensity with the most common exercise being walking. They restrict their calorie intake, stay away from high-fat foods, and watch their portion sizes. They also tend to eat breakfast. But there's a ton of diversity as to what makes up their meals. (Read: again, there was no "best" diet or fad diet that did the trick.) And they count calories.
"Start with a food diary. You need to know where you’re at to know what you should change."
That last point is one that obesity physician and Diet Fix author Dr. Yoni Freedhoff dwells on. "The most important thing to start with is a food diary," he said. "They aren’t sexy or fun, but before you start a diet, you need to know where you’re at to know what you should change."
The food diary should be used before you begin changing your eating habits, to reflect on where you're at, where you may be going wrong, and where you can cut back. Then as you go along in your weight-loss quest, he said, the food diary can help you stay focused. "Keeping a food diary in real time reminds you that you're trying to make healthful choices and change."
The National Weight Control Registry is not a controlled experiment; it does not randomize various weight-loss interventions to groups of people and then see which ones lose weight. Instead, it takes people who are already successful and examines what they did to be so. One thing that this group has in common is that they're clearly highly motivated: they continued weighing themselves, tracking their calories, and limiting their diets — long after they lost weight.
A number of the experts I spoke to said the people they've seen experience a sustained weight loss identified their goals and motivations and hung on to them for the long period it took to slim down and keep the weight off.
To tease this information out of patients, Dr. Matthew Gillman, director of the Obesity Prevention Program at Harvard Medical School, said he always starts by interrogating people about their weight-loss intentions. "I will ask someone what are their goals, and how they envision themselves getting there, and what types of things would allow them to make changes, and then how confident they are in making those changes."
Cornell professor Dr. Brian Wansink said that when people ask him about how to lose weight, he counters with a series of questions. "The most important thing you want to figure out is whether somebody really wants to lose weight," he said. He explained that people might think they want to slim down, but when they actually reflect on the sacrifices and commitment required — realize they aren't ready.
Equally as important, said Dr. Sharma, is to identify barriers to weight loss. "The first thing you want to address is why you're gaining weight in the first place. It could be genetic. It could be stress, having a chronic illness, a medication you're on." There is also a clear correlation between obesity and other social-determinants of health, such as income and education. Obviously, some of these barriers will be easier to overcome than others. But isolating and addressing them wherever possible, he said, is really important for making any sustained lifestyle change.
The message I heard from doctors was remarkably consistent: people who go on diets often set themselves up for failure by expecting results too quickly, picking a plan that either doesn't fit with their lifestyle or is impossible to maintain.
Dr. Maria Collazo-Clavell, a Mayo Clinic obesity specialist, said people go wrong when they think about weight loss on a short time horizon: for a summer holiday, an upcoming wedding. "These short-term approaches do not work," she said.
"The biggest pitfall is trying to lose too much weight too fast," said Canada's Dr. Sharma.
Harvard's Dr. Gillman took a commonsense approach: "People have gained weight over a period of years. They are not going to turn it around overnight. If you try to do that, you’re more likely to regain."
Dr. Freedhoff said he sees people "under-eat, over-exercise, or both at the beginning of weight loss. It's seductive to see the scale go down." But they inevitably fail at maintaining an impossible and unrealistic regimen. "Trying to be too perfect is a huge problem for people in diet world," he added.
"You don't need to be a saint; you need to be a smart sinner," said Dr. Lawrence Cheskin, director of the Johns Hopkins Weight Management Center.
Katherine Zeratsky, a registered dietician at the Mayo Clinic, also said unreasonable expectations — and the self-berating that often ensues — just makes weight loss even more difficult. "When people try and fail, their confidence is so low, and they just lose the confidence to believe they can really sustain even a more reasonable change, or they don't think the reasonable change is going to do much."
Again, these insights should be liberating: change a little at a time, and think long term. Patience, these doctors promised, will pay off.
Another weight loss pitfall people make has to do with the lies we tell ourselves about how much we're eating and burning off.
Studies have found that people very often underestimate how many calories they eat and overestimate how many they use up during exercise. This is easy to do even when you're keeping a food diary.
We play other tricks on ourselves, too: healthy foods sometimes have a "halo effect" and when added to a meal (i.e. cheeseburger with a side of salad) cause people to believe that the overall calorie content of the meal somehow, magically, decreases.
This study found people vastly misjudge the sugar content of fruit juices, believing they are healthy. Dr. Frank Sacks, who has conducted several pivotal studies on diet at the Harvard School of Public Health, said he's seen people make these misjudgments when trying to lose weight time and again. He had a friend who complained about his recent weight gain, and when Dr. Sacks asked him about what he was eating, the friend admitted to drinking the equivalent of 1,000 calories worth of orange juice every day. "That was the biggest single source of calories in his diet," said Sacks.
To get a sense of what you're truly eating, measure your food for a period, suggested Dr. Freedhoff. Use scales and measuring cups in your kitchen. At restaurants, use your hand to help you estimate portion sizes. You won't always need to do this. But you'll quickly learn how much you're actually consuming. And it'll help you to make sure you're not wasting your time with that food diary and delaying the results of your efforts.
The weight loss experts all described to me how they trick themselves and engineer their environments so that maintaining a healthy weight is easier.
As Dr. Sacks said, "In the home, I’ve gotten rid of stuff that I'm likely to overeat. I don't have boxes of cookies on the dining room table that I can just eat. I don't have that stuff around."
Echoing Dr. Sharma's earlier advice, Dr. Freedhoff believes in hunger prevention: he often pre-eats before a meal — usually a small serving of protein, because it's more satiating than carbohydrates — to avoid over-indulging later. He also tries to stay away from alcohol before starting a meal, since there's good evidence that alcohol stimulates appetite and leads to overeating.
Dr. Wansink, of Cornell, is the master of hacking your environment so that healthier choices are easier to make. In his latest book, Slim by Design, he outlines his findings from his behavioral research: he has found that people served from their stove or counter ate 19 percent less food compared to those serving themselves right off the table. He has found that food placement matters: you’re three times more likely to eat the first food you see than the fifth one. In another study, he found that people tend to eat about 60 extra calories per meal when they eat off larger plates, so he suggests replacing 12-inch plates with 10-inch ones.
WATCH: How to health-hack big meals
Now, some of these tips might sound ridiculous — who wants to throw away their plates? — but the underlying theme is sound: environmental cues, not hunger cues, often cause people to overeat.
We might not have control over the temptations we're exposed to outside the home (the cakes and muffins on display as we line up for our coffee in the morning; the giant portion sizes at our favorite lunch spot), but making subtle changes to our surroundings — keeping cookies out of sight, serving ourselves off the stove instead of the dinner table — can nudge us in a healthier direction.
"It's easier to become slim by design than slim by willpower," Wansink said. "Design you change once; willpower you have to do every day for the rest your life."
This review of studies on exercise and weight found that people only lost a small fraction of the weight they expected to given how much they were burning off through their new exercise routines. Some overweight people even gain weight when they start exercising. (You can read more on this here.)
This is partly due to the fact that people develop "compensatory behaviors" when they exercise, thinking they can have those extra treats because of all the work they did, said Tim Caulfield, author of the Cure for Everything. "They go for a run, and then eat a high-calorie muffin, and completely neutralize that run. You're not going to lose weight."
This isn't to say that exercise isn't hugely beneficial for health: it raises mood, protects against disease, boosts energy, and improves sleep quality, just to name a few well-documented benefits.
"I don't have boxes of cookies on the table that I can just eat. I don't have that stuff around."
Physical activity also seems to be important for weight maintenance. In one study, which looked at 20-year weight gain in over 3,500 men and women, those who were physically active gained less weight over time and had smaller waist circumferences compared to inactive people.
But exercise alone isn't going to lead to a great slim down. When a bunch of studies on the question of weight loss and exercise were taken together, researchers found that, overall, exercise led to only modest weight loss. When compared with no treatment, exercise helped people lose a small amount of weight, and when people started to exercise and cut their calories, they lost more weight than with a diet alone. Again, the health benefits of exercise came through in this study: even when exercise was the only intervention for weight loss (so no diet) study participants saw a range of health benefits, reducing their blood pressure and triglycerides in their blood.
The take-home message here: science has shown us that slimming down by exercising alone doesn't work for most people. Physical activity is more important for weight maintenance than for weight loss. What matters most for weight loss is controlling calorie intake.
Overall, the obesity doctors said they were unimpressed by the prescription weight-loss medications that are currently on the market, though some think they might have a role to play in some cases of obesity, particularly when used to complement other lifestyle changes.
Dr. Collazo-Clavell, at the Mayo Clinic, reviewed the literature on diet drugs, and said, "There have been a couple of recent studies, where the people who tend to do best with prescription medical therapies for weight loss are the group initially focusing on lifestyle changes, and lose weight, and then go on to a medication to help." She added: "I do believe these medications have a role but I'd strongly discourage saying they’re the quick and easy fix."
Other doctors were less hopeful. "I'm not using any of these in my practice because the results and/or side effects haven't impressed me," said Dr. Donald Hensrud, who co-chaired the American Heart Association's obesity guidelines. "There's just not a lot of benefit and too many risks."
Dr. Sharma said the medications might be helpful for people who are suffering with other health problems as a result of excess weight, and that interested patients should discuss the harms and benefits with their doctors.
As for supplements that claim to "boost your metabolism" for weight loss, you can just ignore these outright. Nothing you eat can speed up your metabolism to the point of slimming down. What's more, obese people don't necessarily have slower metabolic rates than thin people, so that whole notion is bunk.
"We've measured the resting metabolism in lots of skinny people and in lots of people with serious weight problems, and everything in between," said Dr. Michael Jensen, an expert on metabolism at the Mayo Clinic. "Whether you're above or below average, skinny or obese, as a rule you cannot say obese people have lower metabolism rates than lean people. That's just not true."
"We do know obese people tend to be up and about about two to two-and-a-half hours a day less than lean people," Dr. Jensen said. "My take is the amount of physical activity we do and the amount of calories we take in is far more important than what we do at rest."
Even though you can't control the speed of your metabolism, you can control how many calories you eat and what you burn through physical activity. When people ask Dr. Jensen how to boost their metabolisms, he tells them "go for a walk." That's something supplements like green coffee beans or raspberry ketones just won't do. And it's free.
People who lose weight but don't quite make it to their goal often complain about "the last 10 pounds." Surprisingly, the obesity doctors I spoke to said you should just forget about them if they are that hard to take off.
"If the last 10 pounds are more difficult to lose than the rest, that suggests to me they will be regained," warned Dr. Freedhoff. "If you need to try harder to lose that weight ... the pounds will just come back."
Dr. Cheskin put it even more simply: "It’s not worth it for the last 10 pounds. You’ve gotten almost all of the health benefits and probably most of the social benefits of losing weight if you’ve got two-thirds of where you’d like to be."
He said even losing five percent of your body weight is great for your health. "People should be very pleased with getting partway there."