Three people shopping for lettuce at a farmer's market

The commentary and accompanying video that follows reflect the views of Diana Rodgers, RD, and are not necessarily the views of Harvard Pilgrim Health Care. This is not intended to provide medical guidance in any manner. Anyone interested in pursuing a change to dietary habits should consult with a medical professional prior to taking any action.

In today’s health-obsessed world, it’s actually more complicated than ever to eat healthy. Much of the food at the grocery store has been ultra-processed. You might find that your favorite snack is so delicious that you finish the whole box in one sitting. These foods are considered “hyper-palatable,” meaning that they bypass our brain’s natural “fullness” signals and stimulate us to overeat. In fact, most of our modern, diet-related diseases like obesity and type 2 diabetes often result from eating too much sugar and processed foods.

So, can today’s trendiest diets come to the rescue? My clients ask me about this all the time, and the answer is yes—mostly—with some caveats. But in order to do any of these diets right, you have to understand the reasoning behind them. Some are based on science, some on philosophy, and some on plain old common sense.

Here’s some information on each of these diets—paleo, Whole30®, keto, vegan, flexitarian, and intermittent fasting—that could help you decide if one could be right for you.

Not much of a reader? Here’s a quick, 2-minute video that covers a few of the more popular diets.

The Paleo Diet

The paleo diet centers around unprocessed, whole foods, similar to what a hunter-gatherer would eat. The idea behind it is that the human species evolved eating largely animal proteins and fats, roots and tubers, vegetables, a little fruit, and some nuts.

By eliminating packaged foods and getting back to basics, many people find balance in their blood sugar, lose weight, gain energy, and sleep much better. You may also discover food sensitivities that you didn’t know you had.

Something to be wary of are the “paleo treats” that some companies have started making, which aren’t really the intention of the diet. A brownie is still a brownie, even if it’s made with almond flour.

Is it right for me?

  • Paleo is a very nutrient-dense way of eating, but it requires preparation and time in the kitchen.
  • If you’re used to a lot of takeout, it might be a hard transition, so just take it day by day. You don’t have to give up if you slip up.


Whole30® is less of a diet and more of a 30-day challenge to reset your relationship with food. Like paleo, it sticks to whole foods and can uncover addictions to things like sugar and caffeine. It also maintains a strict policy against some paleo-questionable foods like dairy, honey, and other natural sweeteners. It also cuts out paleo brownies, muffins, waffles, and other treats that mimic junk food. Everything on Whole30® is paleo, but not all paleo food is Whole30® approved.

Is it right for me?

  • Whole30® also requires time and preparation. But many people experience better sleep, more energy, clearer skin, and a reduction in bloating and gas that they thought were normal—in just 30 days!

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The Keto Diet

The ketogenic diet has been a proven medical intervention for epilepsy and even the reversal of type 2 diabetes. By avoiding sugar and sticking to healthy fats, you end up burning more calories from stored fat (ketones) than carbohydrates, which is called ketosis, and can help with weight loss.

If you decide to try keto, it’s helpful to supplement with electrolytes initially to avoid dehydration. And watch out for those hyper-palatable, keto-friendly foods, like fat bombs—a snack designed for the ketogenic diet, which typically involves ingredients like butter, coconut oil, nuts, and seeds. Too many treats like this can make the diet unsuccessful.

Is it right for me?

  • Keto doesn’t work for everyone. Some people are genetically sensitive to saturated fat. For some, a high-fat diet isn’t as satiating as a high-protein diet, and it can be easy to overeat.
  • Unless you have a health condition requiring nutritional ketosis, most people can do well with a general low-carbohydrate and slightly higher-protein diet than many online influencers promote.

Woman buying lettuce at a farmer's market


Veganism is a diet that requires a lot of nutritional knowledge in order to stay healthy. Many Hollywood celebrities have promoted the “clean” virtues of a vegan diet, and it’s becoming a more well-known way of eating. The origins of veganism are tied to many religions and the diet is based on a few ideas—the first being that animal products are unhealthy, followed by the fight for animal rights and, of course, helping the planet.

One thing about going vegan is that it’s critical to supplement with nutrients found in animal products, like B12, choline, iron, and zinc. You should also avoid filling your diet with highly processed foods like pasta, bread, and “vegan” muffins, and instead eat lots of colorful vegetables and protein.

Is it right for me?

  • If you don’t have any medical issues, it could be argued that a whole-food, plant-based diet can be better than the standard American diet.
  • You really need to have knowledge around nutrition, time to spend in the kitchen, and money to buy the supplements.
  • If your body isn’t having bad reactions to animal products, you probably don’t need to cut out such a nutrient-dense food group.


This diet is exactly what it sounds like—a vegetarian who’s flexible about eating animal products. The rules are flexible too, with no real numbers to track for calories or nutrients. In fact, you might call it more of a lifestyle choice rather than a diet.

Flexitarians focus on whole grains, fruits, vegetables, and legumes, and will try to get most of their protein from plants versus animals. But they will enjoy poultry, meat, and/or fish every so often.

Depending on how often you eat animal-sourced foods, you may require nutrient supplementation, which is not ideal, but important to do if you choose this route.

Is it right for me?

  • This is a good option if you’re looking to just cut back on animal products without having hard and fast rules to follow.
  • Diets that focus on whole foods and include lots of vegetables are better than the standard America diet, so as long as you feel good eating this way, it could work.

Intermittent fasting

People didn’t always have 3 meals a day. Before it was possible to just stock up at the grocery store, people would only eat when they had access to food, which might have meant going without for hours or days. Many religions incorporate some sort of fasting, and giving your metabolism a rest instead of a constant stream of food might be a good idea.

It can also be an effective way for some to control caloric intake. However, the overall evidence is not conclusive, and many people overeat when they end their fast. In my experience, a better way to restrict your caloric consumption is to follow this adage: “breakfast like a king, lunch like a queen, and dinner like a pauper.”

Some research shows that fasting at night can be more effective than in the morning—when you eat right before going to sleep, your body is more likely to store the calories as fat rather than burn it for energy.

Is it right for me?

  • This isn’t a great strategy for people who are highly stressed. In fact, it can raise cortisol (the stress hormone), which actually can make you gain weight.
  • Use caution with intermittent fasting if you have an autoimmune or thyroid condition.

Supporting Healthy Eating In Your Community

Healthy food is fundamental to good health. New England’s local produce and meat are delicious and abundant, but too many families still can’t afford it, and national policies needed to make good food cheaper are not on the horizon.

The Harvard Pilgrim Health Care Foundation believes it is up to us to act in our own communities, so that all families can eat better: volunteer to grow, harvest, or deliver produce to food banks or pantries; purchase from local farmers for our own families; join a local commission on land use; and give money to grassroots groups that grow and distribute fresh food for our neighbors. Here’s a source for great ideas to get started.

Here’s what the Harvard Pilgrim Health Care Foundation is doing with Mobile Farmers’ Markets and Growers, Gleaners & Distributors.

Diana Rodgers, RD is a licensed Dietician/Nutritionist