What’s the best diet for weight loss? | CNN

Season 9 of the CNN podcast Chasing Life With Dr. Sanjay Gupta explores the intersection between body weight and health. We delve into a wide range of topics, including the truth about menopausal weight gain and new weight loss drugs. You can listen to the season here.

(CNN) — With dieting, the conventional wisdom says a person needs to be in calorie-deficit mode to lose weight. If you eat more calories than you burn, you gain weight; if you eat fewer calories, you lose weight.

But is that view really right? Doesn’t the kind of food you consume (keto, low-fat, vegan, etc.) and how often you eat (time-restricted eating versus six small meals) matter, too?

Many studies have shown the conventional wisdom — calories in/calories out — is mostly true.

“It is not the only thing, but it is the main thing. And it’s mostly diet, not exercise, because exercising makes you hungrier and you eat more calories,” Christopher Gardner, the Rehnborg Farquhar professor of medicine at Stanford University, told CNN Chief Medical Correspondent Dr. Sanjay Gupta on the podcast Chasing Life recently.

Gardner, who is also the director of nutrition studies at the Stanford Prevention Research Center, has spent decades studying nutrition and food patterns. He was the senior author of a November 2023 study published in the journal JAMA that looked at the cardiometabolic effects of a healthy omnivorous diet versus a healthy vegan diet in identical twins, which was made into the 2024 Netflix limited series “You Are What You Eat: A Twin Experiment.”

Gardner said a very methodical and comprehensive analysis of approximately 20 different diets was published jointly by the American Heart Association, the American College of Cardiology and the Obesity Society in 2013. “And at the end of the day, they said, bottom line is on every one of these diets, people lose weight when there’s a calorie deficit. That was one of the main conclusions, and it was sort of as simple as that.”

But Gardner will be the first to say that there are many important nuances — such as the calorie deficit needed to lose a pound only grows as time on a diet progresses.

“People’s bodies react to that (deficit), and they become more metabolically efficient,” he said. That’s why people’s weight loss starts to plateau. … So the longer you do this and the more weight you lose, the more discouraging it becomes, because it actually takes more effort to lose the next pound, which is psychologically demoralizing for some people.”

There’s another nuance to diets (based on his own research and that of others): Within each type of diet — keto, vegan, low-fat, etc. — some people will lose weight, and others will gain.

“The difference between the diets was just a few pounds. But the difference within each diet was 60 pounds,” he said, discussing his 2017 DietFITS study, noting somebody gained 10 or 15 pounds while another lost around 50. “There’s this huge range of variation.”

So, what’s the secret to successful weight loss?

According to Gardner, there are two aspects. “So, kind of the key to this calorie deficit is it’s stopping your meal soon enough to not overeat and having a long enough space till the next meal, so you’re not making up for that calorie deficit in the next few hours,” he said.

He said he now believes a large part of weight loss success comes down to satiation, noting that what leaves people full can vary greatly.

“I often ask people in some of my talks, ‘Would you be more full and for longer on steel-cut oats with nuts and berries or with cheesy eggs?’ … I often get half the audience saying one (thing) and half the audience saying the other.”

What can you do to maximize your changes of losing weight and keeping it off? Here are Gardner’s top five tips.

Cut back on low-quality carbs and added sugars

Wean yourself off what Gardner calls “crappy carbs.”

“For most people decreasing or eliminating as much added sugar and refined grains will be the biggest bang for your buck,” he said via email, adding that the average American tends to get more than 40% of calories from low-quality carbs and sugars.

But replace those carbs wisely

You can’t just eliminate all those calories from low-quality carbs without replacing at least some of them.

“Shift to adding foods rich in fiber,” Gardner said, listing items such as beans/legumes (which he thinks Americans don’t get enough of), vegetables, whole intact grains and fruits. In addition to fiber, add “sources of unsaturated fat (such as) avocados, nuts, seeds, vegetable oils, fatty fish, whole fat yogurt.”

Stop before you’re stuffed

Practice mindful eating. Pay attention to what you are eating and how you are feeling.

“Experiment with satiety/satiation. Try the Hara Hachi Bu principle of eating until you are 80% full, then stopping,” Gardner recommended, referring to the Okinawan practice of putting down your fork when you are slightly full rather than completely full.  

In essence, it’s an easy way of restricting calories because it allows your body and brain to register how much you have eaten. (It takes a moment for your brain to get the message from your belly that you have eaten enough.)

Change your mindset

Your food choices must be sustainable over the long run whether you pick a diet low in fat, low in carbs or high in protein or choose to follow a Mediterranean, vegan, keto or Paleo diet.

“Don’t think of this as a ‘diet’ that you are going ‘on’ (and) that you will go ‘off’ when you are done,” Gardner said in an email. “It needs to be a dietary approach you can follow FOREVER for the benefits to last.”

For that approach to work, he said, you need to feel satiated, not deprived and hungry all the time.

Show yourself some compassion

Acknowledge it’s not easy to change eating habits to lose weight.

“Be kind to yourself and patient,” Gardner said. “Most people struggle with this. If you beat yourself up psychologically, for setbacks it can be even harder the next time you make an effort.”

Find joy in what you eat

Gardner had one final bonus tip: “You need to find joy and pleasure with what you are eating,” he said. “Allow yourself that for long-term success.”

We hope these five tips help you find an eating pattern that works for you. Listen to the full episode here to hear what Gardner had to say about intermittent fasting. And join us next week on the Chasing Life podcast when Jameela Jamil discusses body neutrality.

CNN Audio’s Grace Walker contributed to this report.

Source: cnn.com