Get full access to Outside Learn, our online education hub featuring in-depth nutrition, fitness and adventure courses, and more than 2,000 instructional videos when you sign up for Outside+..
With dozens of diets out there, it’s easy to get confused. Should you go low-carb, cut calories, try fasting, or omit entire categories of food such as grains or dairy? And how can you tell which diet is best for you?
“They all work,” says David Friedman, ND, author of Food Sanity: How to Eat in
a World of Fads and Fiction. “If you follow the program, you’ll experience the weight loss, but unfortunately, the results are usually temporary.” But there is hope for more permanent weight loss and better weight management.
On the most basic level, Friedman points out, the true meaning of “diet” has been lost. While it’s now synonymous with food restriction, it comes from the Greek word diaita, which means “way of life,” and food is only one part. A plan that embodies the full meaning can succeed in the short term and deliver permanent weight loss, and it doesn’t require turning your life upside down.
Friedman identified three essential parts to a true diet: Getting enough sleep, avoiding obesogens, and eating in a weight-friendly way that’s sustainable. There’s no substitute for restful sleep, because a shortfall will provoke cravings, overeating, and fat storage. Obesogens are chemicals that make us obese by disrupting hormones that regulate appetite and satiety, such as ghrelin and leptin, triggering false hunger signals, blocking our ability to sense when we’ve eaten enough, and stimulating overeating. In food, they include pesticides, herbicides, growth hormones and antibiotics in meat, preservatives, and any other artificial additives.
With a steady stream of such chemicals in your diet, says Friedman, “I don’t care what you eat or what you don’t eat, you’re not going to lose weight.” Eating foods that are organic or produced without chemicals is one essential part of the solution.
The third aspect, eating weight-friendly foods, revolves around the hormone insulin. Starchy and sugary foods raise levels of insulin, and when eaten in excess, lead to fat storage. Reducing such foods makes it easier to lose weight, and many popular diets, including the South Beach Diet and the Zone Diet, embody the premise.
Friedman has one basic rule: Don’t eat the most common white foods, including white flour, white rice, refined sugar, refined salt (chips are out), and dairy (butter and colored cheeses all come from white milk). “Dairy was designed by nature to have a tiny calf turn into a one-ton animal, and milk creates inflammation in the body,” he says. Do eat naturally white fish, poultry, and vegetables, such as cauliflower, jicama, mushrooms, onions, and garlic, but go easy on potatoes. And, he says, naturally un-white whole grains, sweeteners, and salts are fine.
Other ways of shifting to a more weight-friendly diet include fasting, reducing carbs, reducing calories and portions, or eliminating foods that trigger inflammation and health issues, including weight gain.
A New Kind of Fasting
Although it may seem extreme, perhaps even dangerous, today’s meaning of fasting isn’t as drastic as it sounds. Government nutrition surveys show that the norm in 1977 was just three meals a day, without snacks. But by 2004, we were eating about six times daily: breakfast, snack, lunch, snack, dinner, and snack. Because we typically eat so often, a 1970s-era, 12-hour food intermission between dinner and breakfast the next day is now viewed as a fast.
“If you eat all the time, you typically eat more—that’s just logical, really,” says Jason Fung, MD, author of The Obesity Code: Unlocking the Secrets of Weight Loss and founder of the Intensive Dietary Management program in Toronto, Canada, which treats type 2 diabetes and obesity with diet. But that’s not the only pitfall.
By eating all day, says Fung, “You stimulate insulin all the time; you’re giving your body the hormonal instructions to store energy and generally, it becomes body fat.” When we eat more carbohydrates than we need for immediate energy, the excess is stored in the liver as glycogen, and when that “tank” is filled, body fat becomes the storage depot. Giving your body a break from food uses up the energy reserve in the liver, and then body fat gets burned.
Did you know?
Skipping breakfast can be healthier than eating a sugary one.
The Fasting Myth
There’s a theory that going without food for more than two or three hours will bring your metabolism to a halt, but it’s a myth, says Fung. “Your body switches to burning fat and it doesn’t shut down.” That’s why our ancestors were able to survive when food was scarce. “We would have been dead long ago,” he adds, “if we had a requirement to eat six times a day.”
For weight loss, fasting for 24 hours (eating dinner today and nothing until dinner tomorrow, for example) can produce a loss of about a half-pound of fat, plus loss of water weight, and can be done two or three times a week, an approach that’s become known as intermittent fasting. A 36-hour or longer fast is also usually safe and effective for healthy adults. However, fasting isn’t recommended for anyone who is underweight, malnourished, pregnant, or breastfeeding, and anyone taking diabetes or blood pressure medication should work with a knowledgeable physician, as doses will need to be adjusted.
Although a classic fast includes only water, Fung has found that herbal or black tea, bone broth, or coffee, even with a small amount of heavy cream or half-and half, doesn’t impede benefits.
Most people eat about 200 or more grams of carbs daily. Cutting back to 100 grams or less—or even better, to 20 grams daily—will have an effect similar to fasting by exhausting stored energy from the liver and enabling fat burning. If you eat a low-carb diet between fasts, rather than junk food or starchy dishes, says Fung, “you’ll get a better effect.”
“Low-carb” in this sense means eating foods naturally low in carbs, such as leafy greens and nonstarchy vegetables, healthy fats, and lean protein. And avoid artificial sweeteners. An example of a diet with 20 grams of carbs daily might include two fistfuls of leafy greens plus a cup of other, nonstarchy vegetables.
When a body burns fat rather than carbs for energy, it generates chemicals called ketones. Hence the name for “ketogenic” or “keto” diets.
Calorie & Portion Control
Calorie counting continues to be a popular approach to weight loss, but there’s more recognition of the fact that quality of calories matters. Weight Watchers, for example, uses a points system that takes into account how nutritious a food is and how well it fills you up, in addition to calories. Based on age and weight, you get a daily budget of points to “spend” on different foods. Fruits and most vegetables use up zero points, and high-protein foods have a low point value, whereas sugary and starchy foods, and those high in saturated fat, have a comparatively high point value.
The program is designed to produce a weight loss of up to 2 pounds per week, without designating any foods off-limits. Studies have found that it may not produce quite as much weight loss in the first few weeks as a low-carb approach, but is more likely to be sustainable a year later, and is generally more effective than trying to reduce calories and portion sizes without the structured program.
Diets that aim to eliminate triggers of food sensitivities and related health problems may or may not target weight loss, but it can be a welcome side effect. Whole30, for example, is a strict 30-day regimen that eliminates all the major food-intolerance triggers, including grains, dairy, legumes, sugar, and certain food additives.
According to cofounder Melissa Hartwig, it wasn’t designed for weight loss, but 96 percent of people who complete the program lose, on average, between 6 and 15 pounds. On the other hand, the Wheat Belly diet, which eliminates all forms of wheat, refined and whole, was designed for both weight loss and overall health.
Finding Your Own Diet
Would you rather skip some meals and snacks, forego sweet and starchy foods, ditch dairy or wheat, or eat a little of everything but in moderation? Choosing the path that’s most appealing to you is the first step to weight-loss success. Check these out for more info and recipes:
- Dr. David Friedman’s blog: doctordavidfriedman.com/blog
- Dr. Jason Fung’s blog: idmprogram.com/blog
- Low-carb diets and intermittent fasting: dietdoctor.com
- Carb and calorie tracking, apps and online: carbscontrol.com
- Weight Watchers: weightwatchers.com
- Whole30: whole30.com
- Wheat Belly: wheatbelly.com
Weight-Loss Games Can Motivate
Competing against others to reach weight-loss goals has helped many people stay on track. If competition appeals to you, check out:
How to burn off a donut
Divide the number of calories by 100. That’s about how many miles you’d need to walk or run to burn off those calories. A 300-calorie donut takes 3 miles.
The Exercise Myth
While physical activity is definitely necessary and beneficial, and it burns more calories than sitting around or sleeping, it won’t beat an unhealthy or overly generous diet. As a rule of thumb, walking or running a mile burns about 100 calories. Are you willing to literally go the extra mile to burn off a single 100-calorie snack pack, or any of these?