Which Popular Diets Are Healthy Diets?

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

Well, it’s finally official. According to the latest U.S. News and World Report rankings, the Mediterranean diet is the best overall diet for health (and especially so if you want to lose weight or control your diabetes).

While I’m thrilled that the diet is finally getting its due from nutrition, heart disease, diabetes, and weight loss experts – and that people en masse are realizing what a boon it is for wellness – I’m also not the least bit surprised.

I’ve been studying the Mediterranean diet for decades. Not only is the research on point, but time and time again I saw my own patients improve (sometimes even reverse) their diabetes and heart disease with help from the fresh fruits and veggies, lean proteins, healthy fats, and low-glycemic carbs that make up this way of eating. If ever a diet deserved the title of “best,” this is it!

Still, just because the Mediterranean diet is best doesn’t mean it’s the one everyone is trying. There are a lot of eating plans out there, and all of them claim to be good ways to lose weight and get healthy. Low-fat, vegan, keto, Atkins, gluten-free, paleo… Let’s take a look at the good and bad of each one and compare how it stacks up against the Mediterranean.

Best Diet in the World: The PAMM Diet

As bullish as I am on the Mediterranean diet, I like it best with a slight Asian twist. What’s worked best for my patients over the years is adopting a diet that combines the best of traditional Mediterranean and Pan-Asian diets – what I call the Pan-Asian Modified Mediterranean (PAMM) diet. This diet features an abundance of plant-based foods, a good amount of healthy fats, and about 20 percent of calories coming from animal proteins like lamb, fish, chicken and eggs.

The PAMM diet is both a healthy diet and a weight loss diet – a true win-win. With lots of fresh vegetables and fruits, complemented by legumes, fermented soy, eggs, fish and seafood, extra-virgin olive oil, fresh garlic, nuts and seeds, and seaweed, you’re feeding your body low-glycemic, unprocessed, nutrient-dense fuel that’s satisfying, helps keep excess weight off, and promotes health and longevity. Of all the diets out there, I think this one brings us closest to the fountain of youth.

Heart Health Benefits of Olive Oil…Let Me Count the Ways!

Other Popular Diets and Weight Loss Strategies

A High-Carb Diet

The typical American diet is based on processed, quick-to-prepare meals that involve an excess of refined carbohydrates and sugar like bread, bagels, macaroni, and plain pasta. These are all high-glycemic foods that the digestive tract quickly breaks down into sugars and which cause a rapid release of insulin into the bloodstream.

Having a lot of insulin floating around in your blood isn’t going to hurt you if it happens only once in a while – but if you regularly fill up on high-glycemic carbs, you’re setting yourself up for a situation where your cells say, “thanks, but no thanks, insulin, take it somewhere else.” In other words, your cells become insulin resistant. You DON’T want to become insulin resistant; it sets the stage for weight gain, atherosclerosis, diabetes and all the problems these conditions lead to. You’ve got to limit your carbs!

Now – just for the sake of splitting hairs – a high-carb diet can be a healthy diet and a good weight loss strategy if the carbs you eat are low-glycemic and high in fiber. This type of carb is broken down into sugar more slowly, and it doesn’t require much insulin for digestion. Most fresh fruits and vegetables (like the kind you’ll find in my PAMM diet) are best bets as low-glycemic carbs.

Keto and Low-Carb Diets

One of the reasons diets can be so confusing is that one will tell you to eat one way, and another will tell you to do the exact opposite. Like here – you just read about high-carbohydrate diets, and now I’m going to talk about low-carbohydrate diets like the Atkins diet and uber-popular keto diet.

When I say “low carb,” I really mean “almost no carb.” These diets work because you cut your carbohydrate intake so low that your body runs out of sugar to burn for energy, and it has to burn its fat stores instead. In fact, “keto” is short for “ketogenic,” which is the clinical name for being in that fat-burning state.

I agree with the U.S. News rankings that these diets are effective ways to lose weight. I don’t think there’s anything too harmful about them, either, as long as you don’t go overboard with the saturated fats (monounsaturated are best). I’d also stick with organic dairy and eggs to avoid GMOs and pesticides.

What I do worry about is the sustainability of these diets. It’s hard to maintain radical changes in your nutrient intake for more than a few weeks, let alone months. Another long-term issue is that by cutting out most carbs, you’re also missing out on all of the important vitamins, antioxidants, and fiber in fresh fruits and vegetables.

On low- or no-carb diets, some people end up eating way too much meat, cheese, and other animal protein to make up for the lack of carbs in their diets. Through a 2018 study in the Lancet, researchers found that substituting animal proteins for carbs on a low carb diet was associated with a greater risk of mortality than eating a diet of about 50 percent carbs. Conversely, substituting plant-based proteins (nuts, legumes, etc.), decreased risk. Not surprisingly, a high (70+percent)-carb diet was also associated with greater risk of death.

What about a plant-based keto diet? Well, given all the restrictions, I would find it difficult to stay on this kind of diet for very long.

A good diet should be a lifestyle – something you can maintain over the long haul without feeling deprived all the time, and without shorting yourself on vital nutrients. The PAMM diet makes this easy because it offers a wide range of foods to choose from. The only things you’re really denying yourself are high-glycemic, highly processed carbohydrates, which you shouldn’t be eating anyhow.

Very Low-fat or Non-fat Diets

Remember the fat-free diet craze in the 1990s, and how it sparked a whole new industry of non-fat and low-fat foods? Boy, are we a lot smarter now.

At the time, it made sense to assume that a fat-heavy diet would cause weight gain (fat has more than twice the number of calories per gram than carbs or proteins), and it seemed logical that foods high in cholesterol would raise cholesterol levels in the blood. But you know what they say about hindsight – it’s always 20/20.

Now we know that fat – especially saturated fat – was unnecessarily vilified. Worse, the processed, sugar-laden carbs and grains that everyone was substituting for fat were having the opposite effect that everyone expected. They were actually increasing rates of obesity and diabetes!

If weight loss is your goal, research shows that a low-carb diet is by far a better option than a low-fat diet. First, if you’re eating more sugar and processed carbohydrates to make up for the fat loss, you’re increasing your risk of weight gain and diabetes (not to mention arterial disease). Second, fat gives you a feeling of satiety. Depriving yourself of it too much may leave you constantly hungry.

Another thing to remember here is that we need fat in our diet. It’s a key element in a lot of bodily functions, and cutting back too far could have some unintended consequences. For example, limiting your fat intake can affect your levels of omega-3 fatty acids, which are crucial for heart and brain health. So don’t be afraid to eat fat – as long as it’s the right kind of fat.

Fats 101 – Eating for Heart Disease Prevention

I recommend in my PAMM diet that you get 35 to 40 percent of your daily calories from healthy fats like nuts, extra virgin olive oil, avocados, and even organic cheese. These – along with the protein, fiber, antioxidants, and key nutrients the diet provides – are the best weight loss strategy (and it will help keep you out of the cardiologist’s office, too).

A Vegan Diet

vegan diet – which means you don’t eat any animal products whatsoever – is a double-edged sword. On the one hand, if you eat mostly fresh fruits and veggies, legumes, nuts, fermented soy and seeds, you’re doing your heart good. On the other hand, if you eat a diet full of high-glycemic and processed carbs, you’re not doing your heart or waistline any favors.

Either way, vegans risk ending up deficient in a few vital nutrients that are found primarily in animal food sources: vitamin B12 (found in eggs), coenzyme Q10 (CoQ10 – found in fish like salmon), and L-carnitine (found in lamb). We need vitamin B12 to keep our arteries healthy, among other things. CoQ10 – which I wouldn’t dream of practicing cardiology without – is absolutely vital for heart health. Many of my younger patients who were vegans often complained of fatigue, which makes sense given that CoQ10 and L-carnitine are necessary for the production of cellular energy – adenosine triphosphate (ATP).

To make vegan a healthy diet, skip the processed carbs and take vitamin B12, CoQ10, and L-carnitine supplements.

A Gluten-Free Diet

The trendy gluten-free diet doesn’t make a lot of sense to me, but it’s certainly a money-maker for the food industry. Gluten is a protein in wheat, rye, and barley, which means it’s in just about everything in the American diet – breads, pastas, cereals, etc. Grocery stores are now filled with gluten-free versions of all our American favorites, but are these gluten-free foods really any healthier or better for weight loss?

The short answer is, no.

For the portion of the population with celiac disease – about 1 percent – gluten can cause serious health issues. And for people with allergies or sensitivities to foods with gluten, steering clear is beneficial. But for the vast majority drawn to gluten-free processed foods, there’s probably no benefit. A (high-glycemic) carb is a carb is a carb.

(Incidentally, I feel the same way about the lectin-free diet. Lectins are another type of protein that some people are sensitive to but others are not. You’ll realize some benefit from avoiding them if they give you trouble – but if they don’t affect you, there’s not a lot to gain by making a change.)

A big reason why going gluten free isn’t all it’s cracked up to be is that many gluten-free foods substitute processed rice and corn for wheat. So if you’re munching away on gluten-free crackers and eating bowls of gluten-free pasta, you’re not really doing much for yourself other than to be part of a questionable fad (somewhat like the fat-free fad of the 1990s…you see where I’m going with this).

The bottom line? Unless you really have a problem with gluten, a diet where you’re just substituting gluten-free carbs for gluten-filled ones isn’t going to help you lose weight or improve your health. Gluten-free can be a healthy weight loss diet, but only if you cut out the high-glycemic gluten-free carbs, and fill up on fresh fruits and veggies, legumes, nuts, seeds, and other healthy PAMM foods.

Of course, if you have an unexplained illness with bizarre symptoms, you might want to adopt a gluten-free and dairy-free diet, and see if dietary modifications relieve your symptoms.

A Paleo Diet

The Paleolithic diet – or as I like to call it, the caveman diet – consists of what you could hunt and gather if you didn’t have access to supermarkets, bodegas, and restaurants: meat, fish and seafood, fresh fruits and vegetables, eggs, nuts and seeds, and good fats from olive and coconut oils, avocado, and walnuts. It means saying no to modern conveniences like cereal grains, dairy, refined sugar, and processed foods.

Generally, I think Paleo is a healthy diet, as the Paleo diet can help improve symptoms of metabolic syndrome (a condition caused by a carb-heavy diet). However, I’m wary of the overemphasis on meat and the recommendation to eat meat on a daily basis. A few times a week is OK in my book, but not more. Meat-heavy diets are linked to colon cancer, cardiovascular disease, and diabetes. If you go Paleo, make it mostly about the fresh fruits and vegetables and go easy on the meat; mix it up with fish, chicken, eggs, and even fermented tofu.

Food Quality Matters, No Matter What Your Diet Choice

Regardless of which diet you go with, remember that the quality of your food will also impact your results. That’s why, whenever possible, I recommend buying whole, fresh, organic foods. It’s the best way to minimize your exposure to GMOs and pesticides. Plus, organics are less processed (no artificial colors, flavors, or preservatives) so they carry more of the natural energy that they grow with – and the better the energy you feed your body, the better you’ll feel and the healthier you’ll be.


© Stephen Sinatra, MD. All rights reserved.

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