New year, new you: That’s the promise we keep making ourselves, as we’re bombarded with diet ads and promised quick fixes. Even for the most earnest and self-aware new year’s resolutions, whether to lose weight for health reasons or just to eat more healthfully in general, it can be hard to figure out where to start. 

We talked to a few dietitians, who say to minute to assess your options and your body before drastically changing how you eat. There can be many reasons the fast-working diets that influencers tout don’t always lead to long-term or even short-term health. And the most important thing is to listen to the professionals. Let’s get into it. 

1. While a popular plan like the ketogenic diet or intermittent fasting can help you quickly lose weight, they’re not typically sustainable long-term.

Umamah Fatima, a registered dietitian in Chicago: “There’s the instant gratification, the ‘Oh, I’m going to do this diet for a certain amount of weeks and lose a certain amount of pounds, and then I’m fixed.’ But that’s not sustainable, nor is it going to improve your relationship with food or your body. You might lose weight, but if you go back to the same way you’ve been eating before those six weeks, you’ll be back at square one.”

Abigail Taft, a registered dietitian in Cleveland: “On keto, most people do lose weight, but it can also act as a major stressor. It can make you feel really low-energy. It can deplete you of electrolytes. It can cause gastrointestinal issues. You definitely want to be careful and make sure you’re working with someone if you want to do keto. It’s not really sustainable, and it can be really restrictive. If you don’t do it properly, it can cause more harm than good.”

Laura Silver, a registered dietitian in New York City: “There does seem to be a surprising amount of benefits to intermittent fasting, but it’s not game-changing per se. It can be hard to follow. Diets pretend we live in a vacuum, where if it’s good for you, you’ll do it. But with intermittent fasting, what happens if you go out to dinner late? What if you want to go out for breakfast or brunch in the morning? I think anything that forces you to not be social and not live your life isn’t good for you in the long term, because happiness is part of health.”

2. Diets can make you feel disconnected from your body and create a reward-punishment cycle.

Fatima: “You are not only limiting nutrients but also preferences, the enjoyment of food. You’re also adding this reward-and-punishment cycle. A lot of times, a diet can turn into a very disconnected relationship with your body, because you’re saying, ‘I am not going to listen to my body, I’m going to listen to this diet.’”

Silver: “Disordered eating is so wildly normalized that I think a lot of people don’t even realize that their relationship with food could be better. The way dieting works makes your body think more about food. Your body gives you more cravings. You’re also more likely to be all or nothing with food. There’s evidence that the most likely outcome of dieting is actually weight gain rather than weight loss.” 

3. The most sustainable way to reach your goals is to start small.

Taft: “The most sustainable way to lose weight or improve your diet is to use food to create health in your body versus restricting it. When you start to change that narrative, it can help a lot, but you also don’t need to completely overhaul your life. 

“Start with one to two things. I like to start at breakfast — how do you start your day? — and slowly chip away at your entire life, not just food. Think about nutrient deficiencies. Think about your lifestyle. Slowly make changes instead of overhauling your life overnight. Also, don’t put yourself in a box. Diets don’t work; that’s why it’s a billion-dollar industry. Instead, find a way of eating that works for you and makes you feel good.” 

Silver: “Any changes in the short term have to be changes you’re willing to make forever. I encourage people to think about shifting their motivation for why they want to eat well from long-term changes to short-term benefits. That’s not to say those changes are bad, but we want instant gratification. Instead of focusing on losing weight, which might take a while, it’s good to think of short-term benefits in the present, such as saying, ‘It feels good to eat well, and eating well tastes good.’”

4. If you’re looking to lose weight or learn more about nutrition, a professional can offer a personalized approach.

Fatima: “I do a very personalized approach when I work with clients. My approach is balance, variety and moderation. You want to make sure you’re getting a balance of nutrients and a variety in your food. Yes, you can have all the types of vegetables, and yes, you’re going to have cake too, if that’s what you like. I emphasize moderation. You just have to make sure you’re not overdoing it or underdoing it, which can be a challenge, especially when you’re learning how to rebuild that dynamic with food. But also understand what food means to you.“

These interviews have been edited for clarity.

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