Now that it’s the new year, you may be contemplating which diet to try. Before you decide this, it’s helpful to know which are the best diets for weight loss in 2025 (because the research is always evolving) in terms of effectiveness and sustainability. And when I say sustainability, I’m referring to how easy it is to follow a particular eating pattern for more than a few months.
Every year, U.S. News & World Report evaluates hundreds of diets and narrows them to a short list of the healthiest options. This year, instead of a single ranked list, they broke down each diet into different categories, including one for sustainable and fast weight loss. For the purposes of this article, we’re only going to talk about sustainable weight loss diets.
Here are their top picks from their 69-person expert committee of dietitians, medical professionals, and researchers.
The Best Diets for Weight Loss 2025
If weight loss is your goal, here are the 3 best diets for weight loss in 2025 to consider:
- WeightWatchers (4.3 rating): A points-based system emphasizing portion control, flexibility, and lasting weight loss. They promote eating more filling foods like those high in protein and fiber, a more enjoyable approach that helps you create balanced meals throughout the day.
Many of my clients have followed Weight Watchers, or WW, before or while working with me. Their approach is very similar to my own as a sustainable weight loss dietitian – they encourage lasting weight loss through behavior change, solid nutrition science, and plenty of support.
WeightWatchers offers various diet plans with various levels of flexibility, support via its app, recipes, exercise guidance, and more. One of the best offerings they have, in my opinion, is their social network, weekly weigh-ins, and support for life. Weight management is a lifelong commitment, not a 3-month term, and having this continuous support is so essential, even if it’s less frequent as you achieve maintenance. Studies show having accountability helps support long-term weight loss, so I’m always a big advocate of that.
They also offer two other specific support options: one for those with diabetes and another for those taking GLP-1 weight loss medications, as these require specific modifications.
Who this diet may be best for: You’re looking for a balanced way of eating, don’t want to avoid any foods, and thrive off of accountability, a community, and support.
- Mediterranean Diet (3.9 rating): A whole-food approach focusing on fruits, vegetables, whole grains, healthy fats, and lean proteins. The Mediterranean diet is also ranked as the best overall diet for health for the 8th year in a row. If you’re also concerned about your overall health (which hopefully you are, as weight is not the only marker of health), this is surely one to consider.
While there are several variations to the Mediterranean diet (some versions are more plant-based, for example), the basic tenets are the same – they promote longevity, reduce chronic disease, and weight management via a nutritious diet. This diet does not require you to calorie-count like WeightWatchers, but you may find yourself consuming fewer calories by default from eating more whole foods that are filling.
*Of note, while some healthy diets do not require you to track your food, I often find my clients who are the most successful with long-term weight loss log their food on a regular basis (even once they meet their goal).
Who this diet may be best for: You’re looking for a sustainable diet with less processed foods and want to promote better long-term health.
- Volumetrics (3.8 rating): Encourages eating low-calorie, high-volume foods to feel full while consuming fewer calories. This often includes lots of non-starchy, low-calorie veggies like leafy greens, broccoli, cauliflower, asparagus, fruits, plenty of water, and lean proteins. These veggies and fruits are naturally low in calories but high in fiber and water content, so you can load up on them to keep you full. Eating them first helps promote fullness without a lot of calories, which leaves less room for more calorie-heavy items like bread, pasta, or pizza.
Who this diet may be best for: You’re a volume eater and need a lot of bulk to feel full. It can also be helpful if you eat very fast and therefore end up eating too much. In this way, you may still consume large portions, but you can more easily stay within your calorie allotment to lose weight since most foods included are naturally lower in calories.
Learn more about the Volumetrics diet and volume eating here in my post Volume Eating: What Is It?
Not sure where to start? Check out my blog: How to Create a Meal Plan for Weight Loss.
2025 Diets to Approach with Caution
On the other end of the spectrum, the lowest-rated diets for 2025 include the AIP (Autoimmune Protocol) diet, BRAT (Bananas, Rice, Applesauce, Toast) diet, and SlimFast. These scored poorly due to being overly restrictive, lacking scientific backing, or focusing heavily on branded products.
Unless prescribed by your physician under strict supervision, these diets can lead to unnecessary deficiencies and harm health.
What Makes a Diet Effective for Weight Loss?
When evaluating the best diets for weight loss in 2025, the expert U.S. News panel considered nutritional completeness, health risks and benefits, long-term sustainability, and evidence-based effectiveness. These factors helped identify diets that not only promote weight loss but also support overall health and are realistic to maintain over time.
As mentioned above, the list also includes the best diets for fast weight loss, which include Jenny Craig, Keto, and SlimFast. However, while they may promote faster weight loss, they are ranked lower overall by the experts for sustainability and overall health. Remember, fast weight loss does not lead to long-term weight loss.
Consider Other Health Goals and Preferences
While weight loss is a common focus, the best overall diets also emphasize broader health benefits. For more on the best diets for different health conditions and goals, see the U.S. News & World Report List for categories such as Best for Diabetes, Best for Heart Health, and more.
How to Choose The Best Diet for You?
Before embarking on any diet change, it’s helpful to know which diets are the most evidence-based. But, it’s equally essential to do some introspection first.
This means taking some time to think about what has worked or not worked for you in the past. There is no sense in returning to the same diet that didn’t lead to lasting results several times expecting a different outcome. So before you jump back on your healthy eating journey, make sure not to skip this necessary step.
Here are a few things to ask yourself before starting a new diet:
Does this diet fit my lifestyle and preferences?
Consider whether the diet aligns with your daily routine, cultural food preferences, and social commitments. A sustainable diet should feel realistic and adaptable to your life and should not require you to eat completely differently than your family. When I counsel clients, our goal is to ensure only one meal needs to be made for the entire family.
Can I see myself following this long-term?
Weight loss diets that are overly restrictive or require constant willpower often fail in the long run. Look for a plan that feels balanced and enjoyable so it becomes a lasting habit.
Does this diet provide enough variety and nutrients?
Ensure the diet includes a wide range of foods to meet your nutritional needs, prevent deficiencies, and keep meals satisfying and interesting.
Is the diet backed by credible science?
Avoid fads and trends that promise quick fixes. Choose a diet supported by research and evidence for its effectiveness in promoting sustainable weight loss and overall health.
Every diet can lead to a temporary weight loss plateau or slow down, but asking yourself these questions can help you find the best option for you.
A few red flags to look for
The diet removes entire food groups or requires you to eat less than 1,200 calories per day.
While cutting calories is necessary to lose weight, going too low can actually backfire. Many of my clients are often skeptical of this fact but then are pleasantly surprised that they can eat more and experience more weight loss. This is because very low calorie diets below 1,200 calories promote fast weight loss but are more associated with weight regain. They are also challenging to stick to and just drag out the yo-yo diet cycle.
The diet requires you to prepare meals you don’t have time for.
If the diet and food prep doesn’t fit your schedule, it’s not the diet for you. While you may feel motivated those first couple of weeks while you’re making initial changes, a sustainable weight loss plan has to fit within your life and schedule constraints. If it doesn’t, life will keep coming up and getting in your way. This is not to deter you from cooking and meal prepping – but you have to be realistic with the amount of time you have. A healthy meal can be made in 15-20 minutes, so if that’s all you have, it’s okay to be honest with yourself.
The diet causes you to feel hungry or tired.
If any diet makes you feel unsatisfied, hungry, or run down, it’s not the diet for you. You shouldn’t have to “stick it out” and deal with it until your body gets used to it. If a way of eating makes you feel worse, it’s a sign it’s not best for you.
A prime example is intermittent fasting.
Some people feel great on it, while others don’t. If you’re following a plan for more than a couple of weeks and don’t feel better physically and mentally, don’t torture yourself – find something that matches what you personally need. And if you feel hungry all the time, you’re setting yourself up for overeating and bingeing, so don’t make things harder than they have to be.
The Bottom Line
When choosing among the best diets for weight loss in 2025, it’s crucial to prioritize sustainability and alignment with your personal preferences and lifestyle. While food is foundational to health, remember that physical activity, stress management, quality sleep, and meaningful relationships contribute equally to overall well-being.
Whether your goal is weight loss or long-term health, the best diet is one that you can stick to and enjoy to maintain your weight loss. Explore meal plans and recipes from the top diets to find what works for you, and if you can’t figure it out, this is where I come in.
In my sustainable weight loss program, I help you establish small, sustainable changes that lead to lasting results. If you want to do things better in 2025, contact me to schedule a free nutrition call. We’ll talk through your goals, answer any questions you have, and determine how I can best help you in your journey!
