What’s the best diet plan? USC experts evaluate 4 popular trends
Are you thinking of trying that trendy diet your friends raved about on Instagram? Before you declare the latest celebrity fad the best diet plan, check the science first. While many diets promise quick weight loss, they often have a downside. We asked two USC experts to help us separate truth from hype for four popular diets that many claim to be the best diet plan. Here’s what we learned:
Diet plan: High protein, low carb
Popular diets such as Atkins and paleolithic (or “paleo”) emphasize high-protein foods throughout and low carbohydrates during their initial phases. Later on, both diets slowly add back carbohydrates. Paleo, however, eliminates grains, legumes, and dairy.
The Good: Few hunger pangs since protein helps to suppress your appetite. Many rave that low-carb is the best diet plan because you’ll lose weight as the diet causes your body to enter “ketosis,” a process that shifts it from using carbs to burning fat for fuel. Removing sugars, starchy food, and refined flour also improves your insulin levels. “The more carbs you can cut out, the better, especially sugars and highly processed foods, which tend to be higher in carbs,” said Michael Goran, co-director of the Diabetes and Obesity Research Institute at Keck School of Medicine of USC. “A high-carb diet generates a lot of glucose, which means you must produce more insulin to clear it. This stresses your body and, over time, can contribute to cardiovascular disease or diabetes risk.”
The Bad: Cutting carbs at the most extreme level can lead to eliminating fresh fruit and vegetables, which means you miss out on their nutritional benefits. Eating a lot of protein without fiber can lead to constipation, especially at the start. You may also feel tired and irritable during the first two weeks as your body shifts to burning fat for energy. Emphasizing meat protein leads to consuming too much saturated fat — incredibly when plant-based sources like beans and legumes are restricted or eliminated.
Diet plan: Ketogenic (Keto)
The ketogenic diet is a variation of Atkins that calls for extremely low carbohydrates, moderate protein, and high fat.
The Good: Like Atkins, the diet lowers insulin levels and shifts your body to burning fat. It may also improve your cholesterol levels.
The Bad: When you decrease your fiber intake drastically, you’re at a higher risk for constipation. The diet also leaves you feeling grumpy for the first few weeks. “That’s because you lose the serotonin and the energy you normally get from carbohydrates,” said Claudia Del Vecchio, nutrition educator at Keck Hospital of USC. “A lot of people also go through sugar withdrawal and feel edgy. But after a few weeks, they feel better.” This is not the best diet plan for all though: it should be avoided by anyone with kidney issues because constant ketosis changes urine chemistry and raises the risk of developing kidney stones.
Diet plan: Juice cleanses
Made of fruit, vegetables, or a combination of juices, this liquid diet reduces calories and mimics fasting. If done for more than two days, it also shifts the body into burning fat for energy.
The Good: It lowers insulin levels and allows your metabolic system to rest. “By resting the processes involved in digesting food, you reduce things like stress hormones and insulin-like growth factors, which may reduce your cancer risk,” Goran said.
The Bad: You’ll probably feel hungry. If you drink a lot of fruit juice, you may feel moody as your blood sugar surges and then drops. If a cleanse lasts more than a few days, your body thinks it’s starving and shifts to burning fewer calories. Also, if you’re opting for juice instead of eating whole fruit, you’re getting a high dose of sugar but none of the fiber that can slow down absorption and make you feel fuller.
Diet plan: Raw foods
This diet typically includes raw vegetables, fruit, nuts, and sprouted grains. Some versions include unpasteurized dairy, raw eggs, or fish.
The Good: You’ll get plenty of fiber, vitamins, and minerals by eating whole, unprocessed food.
The Bad: Because it’s so high in fiber, you may feel gassy, and bloated, and have frequent bowel movements. You may also get exposed to toxins in some raw foods or miss out on nutrients that are more easily absorbed when food is cooked. “For example, the antioxidant lycopene in tomatoes is more bioavailable when the tomatoes are heated than when eaten raw,” Del Vecchio said. “Button mushrooms contain carcinogens that get destroyed only when cooked.”
While all four diets can help you lose weight, Goran recommends the best diet plan as one for long-term good health. Stick with a balanced diet, which includes whole foods and plenty of fruits and vegetables, and cut out highly processed foods, sugar, and simple carbs. For the best and healthiest way to sustain your goals, Del Vecchio recommends consulting with a nutritionist or medical provider — not Instagram — to determine guidelines that best match your lifestyle and health background.
The "best" diet plan can vary significantly from person to person, depending on individual goals, preferences, health conditions, and lifestyle. There is no one-size-fits-all approach to diet, and what works for one person may not work for another. That said, here are some general principles and popular diet plans that may help guide you in choosing a diet that suits your needs:
Balanced Diet: A balanced diet includes a variety of foods from all food groups in the right proportions. It typically consists of fruits, vegetables, lean proteins, whole grains, and healthy fats. It can be a good choice for overall health and well-being.
Mediterranean Diet: The Mediterranean diet is renowned for its health benefits. It emphasizes whole foods like fruits, vegetables, whole grains, nuts, seeds, olive oil, and lean protein sources like fish and poultry. It's associated with a reduced risk of heart disease and other chronic conditions.
Vegetarian or Vegan Diet: Vegetarian and vegan diets exclude some or all animal products. They can be suitable for those who want to reduce their environmental impact, lower cholesterol levels, or manage weight. It's essential to ensure you get all the necessary nutrients on these diets.
Ketogenic Diet: The ketogenic diet is very low in carbohydrates and high in fats. It's used primarily for weight loss and managing certain medical conditions. This diet can be effective but may not be suitable for everyone, and it should be followed under medical supervision.
Paleo Diet: The paleo diet encourages eating whole foods that our hunter-gatherer ancestors would have consumed. It includes lean meats, fish, fruits, vegetables, nuts, and seeds while excluding processed foods, grains, and dairy. It's focused on whole, unprocessed foods.
Low-Carb Diet: Low-carb diets restrict carbohydrate intake, which can lead to weight loss and improved blood sugar control. Popular low-carb diets include the Atkins diet and the South Beach diet.
Intermittent Fasting: Intermittent fasting involves cycling between periods of eating and fasting. It can aid in weight loss, improve insulin sensitivity, and support metabolic health. There are various methods, such as the 16/8 method, where you fast for 16 hours and eat during an 8-hour window.
DASH Diet: The Dietary Approaches to Stop Hypertension (DASH) diet is designed to lower blood pressure. It focuses on reducing sodium intake and emphasizes fruits, vegetables, whole grains, lean proteins, and low-fat dairy products.