For long-term success, there are better (and more enjoyable) options.
Reviewed by Dietitian Katey Davidson, M.Sc.FN, RD, CPT
Key Points
- Restrictive diets may lead to short-term results but are hard to sustain.
- Flexible, balanced eating patterns are more realistic for long-term success.
- Dietitians say sustainable weight loss doesn’t require cutting entire food groups.
There’s no shortage of weight-loss advice (both good and bad) available online and on social media. From one scroll to the next, you’ll hear people singing the praises of everything from low-carb diets to GLP-1s and celery juice. The problem is that a lot of trendy diets overpromise and underdeliver—making it hard to know what actually works.
To help you sort through the noise, we asked dietitians to share which trendy diets they wish people would skip, especially when trying to lose weight. These are the top three diets they said probably aren’t worth your time.
1. Keto Diet
Variations of a low-carb diet have been around for years—from Atkins to keto to the carnivore diet. Any way you slice it (hold the bread), these drastically carb-restricted diets aren’t generally recommended by dietitians.
Let’s take the keto diet, for instance. “The premise—slashing carbs to force the body into ketosis—sounds compelling, but the reality is that most people can’t sustain it long-term,” says Lisa Young, Ph.D., RDN., CDN. “It eliminates entire food groups, including fruits, legumes and whole grains, that have decades of research behind them for heart health and longevity.”
Although some individuals may see short-term success, the diet has low long-term adherence due to its strict nature and unwanted side effects that may impact overall health. In particular, it may lead to poorer gut health and changes to the gut microbiome since gut-supporting foods—like fiber—are limited. Research continues to show that including a variety of foods in your diet is linked to better microbial diversity in the gut, which is important for supporting a healthy gut, reducing inflammation and lowering risk of chronic disease.
The popularity of low-carb diets like keto has also played a big role in the stigma around carbs. “I see clients develop a fear of carbohydrates that outlasts the diet itself, which can be genuinely damaging to their relationship with food,” says Young. Rather than focusing on the quantity of carbs you’re eating, shift the focus to quality. Choose higher-quality carbs like whole grains, beans, fruits and vegetables more often than sugary drinks and baked goods.
2. Intermittent Fasting
Intermittent fasting, or time-restricted eating, focuses less on what you’re eating and more on when you’re eating. The premise is that you have set periods or “windows” of fasting and eating, and that by shortening your eating window you can encourage weight loss and better metabolic health.
It sounds promising, especially since you aren’t cutting out whole food groups like with other diets, but here’s why dietitians aren’t a fan of intermittent fasting. “Your body might benefit from short-term fasting, as it can help reduce bloating and blood sugar levels, but long-term is a different story,” says Lisa Moskovitz, RD, CDN. “Too many of my clients end up struggling with energy, muscle loss and food noise as a result of time-restricted eating.” Food noise is when a person becomes preoccupied with food-related decisions, often ruminating about food throughout the day. Restricting yourself to certain eating windows may mean pushing through true hunger, which is counterproductive to mindful eating.
“As a dietitian, I see people becoming disconnected from their hunger cues, overly focused on food or stuck in a cycle of restriction and overeating,” says Paloma Vega, M.S., RDN. “Healthy eating patterns should feel realistic, nourishing and sustainable long-term.”
To be fair, some individuals genuinely enjoy intermittent fasting and may see positive results, but that doesn’t mean it’s right for everyone—especially when rigid eating windows interfere with hunger cues, social life or overall energy levels.
In addition, Moskovitz finds that the popular 16:8 fasting method—where your eating window is only eight hours—often leads to skipping breakfast, which is a pivotal mealtime to consume more protein and fiber to support metabolic health. In some cases, it may lead to overeating later in the day since you’re very hungry.
For weight loss, research suggests that intermittent fasting doesn’t outperform a calorie-restricted diet. Instead, following a balanced diet that allows for flexibility in eating times is likely more sustainable and enjoyable, while still helping you achieve the results you want.
3. Paleo Diet
“The paleo diet has been around for a while, but I wish people would let it go,” says Sara Riehm, RD, LD/N, CSOWM.
The premise of this diet is that we should eat like our hunter-gatherer ancestors, because the modern Western diet is to blame for chronic disease. There are some benefits to the paleo diet, largely that it emphasizes whole foods, fruits, vegetables, healthy fats and proteins while limiting ultra-processed foods, sugar and salt—an eating style linked to better health outcomes.
On the other hand, the paleo diet encourages you to cut out grains, legumes and dairy—foods that are naturally nutrient-dense and associated with positive health benefits.
Riehm says that whole grains and legumes are packed with fiber, which can help manage blood sugar, control cholesterol and improve digestive health. In addition, dairy is an important source of calcium and is often fortified with vitamin D. “When we cut those out of our diet, we’re missing out on lots of potential nutrients and restricting ourselves in a way that isn’t sustainable for most people,” says Riehm. “It’s not necessary to cut out whole food groups in order to lose weight.”
So, while following the positive aspects of the diet may be helpful for overall health and potentially weight loss, there’s no need to follow it entirely.
What to Do Instead
Rather than hopping from the latest trendy diet to the next, try some of these dietitian-approved tips to help you achieve your weight-loss or health goals.
- Focus on Addition, Not Subtraction. “Instead of cutting foods out, ask what you can add—more vegetables, more fiber, more protein. This naturally crowds out less-nutritious choices without triggering deprivation,” says Young.
- Embrace Flexibility. “It’s so important to remain flexible on a weight-loss journey to make it sustainable. This means including a variety of foods, not being too restrictive and knowing that when a less-than-perfect day happens, we can move on from it,” says Riehm.
- Don’t Weigh Yourself Daily. When you are weighing yourself everyday, it can be easy to fixate on the number on the scale—but it’s normal and natural for our weight to fluctuate. That’s why Riehm suggests stepping on the scale once a week instead. “On a weight-loss journey, it’s important to still track your weight in the name of self-monitoring and accountability, but we want to look at the overall trend, not the little fluctuations. If you’re seeing an overall downward trend in the bigger picture, that’s success.”
- Don’t Overlook Sleep and Stress. “Sleep and stress matter as much as food. Cortisol and sleep deprivation directly affect hunger hormones. Clients who address these often see results that no diet delivered,” says Young.
- Work with a Dietitian. Dietitians are trained to help support your health and weight-loss journey by providing a personalized plan that suits your unique needs.
Our Expert Take
Trendy diets promise big results, but they rarely deliver long-term success—often because unnecessary food rules and restrictions make them difficult to sustain. Some popular diets of the moment include the keto diet, intermittent fasting and paleo, but dietitians recommend skipping them.
Instead, dietitians say that the best strategy for weight loss is a balanced, nonrestrictive eating pattern that you can maintain long-term. What’s more, speaking with a registered dietitian can help you get started in the right direction with personalized advice for lasting success.
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