When done safely and appropriately, weight loss can improve health and reduce the risk of chronic conditions like type 2 diabetes, liver disease, certain cancers, and heart disease. However, many diets that promise fast results rely on extreme tactics that often harm your health more than help it. Here are five diets registered dietitians recommend avoiding, along with what to do instead.
Low-calorie diets are typically defined as diets that provide between 1,000–1,500 calories per day, which is low for most people. Very low-calorie diets (VLCDs) are more extreme, providing less than 800 calories per day.
Eating in such an extreme calorie deficit can lead to nutrient deficiencies, loss of muscle mass, and decreased energy over time. Studies also show that restricting calories too drastically can also slow metabolism, making it harder to maintain weight loss over time.
Another concern with VLCDs is that they can cause unpleasant side effects, including intense hunger, irritability, and low energy levels.
What to do instead: Instead of following VLCDs, aim for a modest calorie reduction paired with increased physical activity. Most health experts suggest slow weight loss, about 1 to 2 pounds per week. This supports long-term weight-loss success and helps preserve muscle mass, maintain a healthy metabolism, and prevent side effects such as intense hunger.
The Carnivore Diet is highly restrictive, cutting out plant foods and relying entirely on animal products for nutrients. Followers of this diet claim it can promote weight loss and improve health markers, like blood sugar and triglyceride levels.
Though very limited research shows that the Carnivore Diet may lead to short-term improvements in weight and blood sugar, this eating pattern isn’t appropriate or necessary for most people. It is deficient in fiber, vitamins, and minerals like thiamin, magnesium, calcium, vitamin C, and folate.
Plus, eating exclusively animal products could lead to side effects like constipation and low mood, and increase the long-term risk of colorectal, breast, and colon cancer and heart disease.
What to do instead: For most people, a balanced diet that includes both plant and animal foods is the healthiest approach. Plant foods provide fiber, a nutrient that plays a vital role in digestion and appetite control.
While incorporating juices into your diet is an easy and effective way to boost your intake of vitamins, minerals, and antioxidants, juice cleanses should generally be avoided for weight loss purposes.
Studies show that even short-term juice fasts, such as three-day juice fasts, can negatively impact digestive health and increase the number of gut bacteria associated with gut permeability, inflammation, and cognitive decline.
Additionally, juice cleanses are low in fiber and high in sugar, and can lead to side effects such as gas, dizziness, fatigue, and hunger pangs.
What to do instead: If you want to include juices, such as green juices, in your routine, it’s best to enjoy them as part of a balanced diet, like pairing a green juice with a healthy lunch or having citrus juice alongside a protein-rich breakfast.
Diets that rely on a single food or drink, such as the cabbage soup diet, grapefruit diet, or Master Cleanse drink diet, as well as diets that rely on a single food group, like the fruitarian diet, are unsafe and lack key nutrients your body needs to function.
Though these diets are popular amongst those who want fast results, they can cause nutrient deficiencies and dangerous side effects, like kidney issues and electrolyte imbalances.
These highly restrictive diets can also lead to symptoms like irritability, fatigue, and intense hunger, and trigger cravings for restricted foods.
What to do instead: Create an eating pattern that naturally supports weight loss by helping you feel full, leading to fewer cravings and lower overall calorie intake, such as high-protein, high-fiber diets.
Though they’re becoming less popular, very low-fat diets are still used by those wanting to shed excess pounds.
While it’s true that eating diets too high in certain kinds of fats, like saturated fat, can lead to health concerns, like an increased risk of certain cancers, fat is essential for health and cutting all high-fat foods from your diet isn’t necessary for weight loss.
In fact, research shows that low-fat diets aren’t as effective for weight loss as other diets, such as low-carb and high-protein diets.
Additionally, many “low-fat” products are higher in refined carbs and added sugars than their regular-fat counterparts. Replacing nutritious, high-fat foods with low-fat versions can negatively affect health by raising blood sugar and triglyceride levels.
What to do instead: Although some people need to follow lower-fat diets for health reasons, most people can consume a balanced diet containing high-fat, nutritious foods like avocados, olive oil, nuts, and full-fat dairy.
If you’re interested in trying a new diet, it’s important to consider your individual health needs, goals, and dietary preferences before choosing an eating pattern.
Here are a few tips to help you narrow down the safest and healthiest diet:
- Check in with a healthcare provider: A healthcare provider, like a doctor or registered dietitian, can help you choose a diet that’s appropriate for your needs, considering factors like existing health conditions or a history of disordered eating.
- Choose sustainability over short-term results: Rather than opting for a short-term, rapid-weight-loss plan, choose a diet you can maintain long-term that supports both healthy weight management and overall well-being.
- Pay attention to diet quality: Many weight-loss-centered diets cut out foods rich in key nutrients, such as protein, healthy fats, and fiber. Healthy and balanced meal plans are high in nutritious foods and aren’t unnecessarily restrictive.
- Avoid extreme restriction: While reducing foods high in added sugar or fast food can support weight loss and overall health, extreme calorie restriction or eliminating entire food groups can backfire, causing nutrient deficiencies, extreme hunger, and more unpleasant side effects.
- Be wary of extreme claims: Diets that promise rapid or “too good to be true” results often carry risks. While extreme diets, such as juice cleanses, may lead to quick weight loss, they can harm your health and cause dangerous side effects.
It’s also important to note that many weight-loss-centered diets can be particularly harmful for certain groups. For example, people with a history of disordered eating and those with health conditions like diabetes and kidney disease may be at increased risk of dangerous side effects from highly restrictive diets.
