As humans, we’re constantly subscribing to new diets, eating plans, workout clothes, and useless devices we buy off Amazon only to ditch completely a few weeks in. We cut out carbs, eat like cavemen, try the Greek, Miami, and/or Keto diets and only eat between the hours of 11am-7pm. And while a few of these diets may actually help us shed a few pounds, are these diets actually helping us? Or are they causing more harm than good?

Generally speaking, anything that helps us lose weight has to be good, right? Weight loss = skinny jeans. Sounds good to us. But we’re not doctors, so we went to someone who knows their stuff. Dr. Kimberly Parks is the Medical Director of Synergy Private Health in Boston and an Assistant Professor of Medicine at Harvard Medical School. A board-certified cardiologist and internal medicine specialist, she focuses on lifestyle and culinary medicine, using dietary patterns to improve health. With a large teaching kitchen at her practice, she also hosts cooking classes to teach patients how to easily incorporate healthy, delicious food into their diets.

So we asked — how bad are those trendy diets we keep trying year after year? Turns out, it depends entirely on which diet you’re choosing, how long you’re on it, and how the foods you’re eating are relative to your health. If you swear by your Keto regime, good news! It’s not that bad for you. “It was originally developed to help reduce seizures in people with epilepsy, but is incredibly popular and can work well for short term weight loss,” explains Dr. Parks. “There are even small studies showing improvement in metabolic indices in patients with diabetes while following a Keto diet.” In short, small intervals, Keto can actually benefit your health.

But if you’re in it for the long haul, you may want to rethink your eating habits. “I have major concerns about the long term impact of the Keto diet on a person’s risk for cardiovascular disease, as most people who follow the Keto diet tend to eat high amounts of saturated fats in place of carbohydrates,” Dr. Parks notes. “High intake of saturated fat is linked to development of cardiovascular disease, the number one killer of both men and women. CVD occurs over many years, and most studies assessing the health benefits of the Keto diet are shorter term.”

If you’re dedicated to your Keto and can’t be deterred, there are healthy ways to make this diet work for you, but only if you’re focusing on plant-based proteins and cutting down on saturated fats. “The biggest issue with the Keto diet is that it is difficult for many people to follow as it has very strict requirements in terms of intake of macronutrients, therefore making it difficult to sustain long-term,” she explains. “Additionally, I worry about the elimination of health-promoting foods such as certain fruits and vegetables.”

But Keto is so 2018. If you started intermittent fasting in 2019, you’re in good company. “I personally have subscribed to intermittent fasting as well as a vegan diet,” explains Dr. Parks. “The benefits of intermittent fasting are best if you’ve already been eating nutrient dense foods.” It’s a great way to help your body lose weight, especially if you already eat healthy and exercise but just can’t lose those last 10 pounds. “The time-restricted eating patterns do help in addition to restricting overall calories… but when it comes to weight loss, at the end of the day it really comes down to calories. If you have taken in more caloric energy than you expend, you will gain weight, regardless of the calorie source.”

If you are practicing intermittent fasting while eating healthy and incorporating the best foods from all major food groups, you’re on your way to a healthier and leaner body. “There are two main methods of IF, the 8:16 and the 5:2 plans. Both have been demonstrated to have some health benefits including weight loss and reduced incidence of type 2 diabetes. I have had success with this in my practice, particularly in people who are eating high-quality foods but still aren’t achieving the desired weight loss they would like,” she explains. “The important thing about intermittent fasting is that during the feeding phase, it’s important to focus on high quality foods rather than using it as a way to eat whatever you’d like.” In this diet, broccoli is still on the menu, but with its less restrictive guidelines, it’s easier to still incorporate the foods you love.

If you don’t like the regimen of intermittent fasting or the restrictions of Keto, there are plenty of diets to choose from, but as Dr. Parks explains, jumping from diet to diet can actually hurt more than help. 

“There are several drawbacks to adopting a new fad diet. First, many of them are not sustainable, and while they may lead to rapid weight loss while on them, there’s a rebound effect once a person resumes their usual eating habits.”

And while we love the idea of rapid weight loss, is it worth if it we gain it all back once we try to return to our everyday eating habits? If you’ve ever been a yo-yo dieter, you know the struggle of gaining and losing weight only to gain it all back again. 

Make sure that if you do start one of these fad diets, you watch what you’re actually putting into your body. “Some of these diets could hurt long-term health by depriving the body of certain healthy nutrients,” Dr. Park adds, noting that many fad diets focus on taking out an entire food group and focusing solely on the other two. (For example, eating proteins and fats and cutting out carbs — when your diet suddenly consists of entirely protein, you could be putting your health in danger.)

In fact, Dr. Parks considers most of the fad diets we’ve subscribed to in the past a hazard to our health. “I consider any diet that puts restrictions on major food groups dangerous. They’re easy for promoting short term weight loss, but at what cost long term?” she asks. “When we look at dietary patterns of people who live the longest, they eat a variety of foods, and foods that are mostly plant based.” Even the doctor herself sticks to a vegan lifestyle. “The Atkins, Carnivore, and Keto diets emphasize fats and meats and restrict healthy, nutrient-dense carbohydrates such as whole grains — think oats, faro, barley — and certain fruits. Lack of whole grains has been linked to heart disease as well as worsen kidney function in people with underlying kidney disease. There is also a link between high intake of red meat and colon cancer, and many of these low carb diets naturally lead to higher consumption of red meat and dairy.”

So what’s the healthiest way for us to say goodbye to oversized sweaters and hello to bikini season? 

“The safest and best way to lose weight and get healthy is not by following a particular fad diet, but rather adopting a healthy dietary pattern that can be sustained throughout life,” Dr. Parks explains.

“In my practice, we teach our patients how to find healthy foods they enjoy and how to make them taste delicious. A healthy diet pattern should not feel restricted; the focus should be on eating high-quality, whole foods that are not processed, increasing intake of whole grains and vegetables, eliminating processed foods, and avoiding the high intake of calorie dense foods such as oils, nuts, and dried fruits.”

We need to eat in a way that is mindful and healthy, focusing on what our bodies need rather than whatever new fad the next month will bring. “Incorporating mindfulness into eating means being mindful of eating slowly, listening to our bodies cues about hunger and satiety, being mindful of our choices, how they impact our health, and how they impact the environment,” Dr. Parks says. “I like to adopt the basic rule as quoted by Michael Pollen: ‘Eat food, mostly plants, not too much.’ Adopting these basic principles is a great way to have a healthy, sustainable eating plan.”

Marissa Stempien is a freelance editor and writer. With a degree in English Literature and a minor in Asian Studies, she has written on travel, fashion, beauty, technology, culture, and food, and enjoys writing short stories in her spare time. Find her on social media at @paperandlights.

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