The 2019 rankings include 41 of today’s most popular diets. New to the list this year is the Nordic Diet, a plant-heavy eating plan that incorporates Scandinavian traditions and ranked 9th best overall. Here’s how the rest of the rankings shook out this year, and what experts have to say about the good, the bad, and the trendy. (Here’s a hint: They’re still not crazy about keto.)
I have multiple autoimmune diseases. I fought 4 doctors, all of whom told me that adults can’t get type 1. I finally went to the Jefferson Diabetes Center. Yup! Type 1 diabetes. I’m slender, do marathons, bp 100/60, triglyceride/HDL ratio 1.08. And I STILL fought 4 doctors because of the ADA misinformation. All it takes is a simple blood test to look at antibodies. That’s all it takes, but the test is almost never run.
There are three instances where there’s research to back up a ketogenic diet, including to help control type 2 diabetes, as part of epilepsy treatment, or for weight loss, says Mattinson. “In terms of diabetes, there is some promising research showing that the ketogenic diet may improve glycemic control. It may cause a reduction in A1C — a key test for diabetes that measures a person’s average blood sugar control over two to three months — something that may help you reduce medication use,” she says.

I’ve been there and have tried the Ketogenic Diet. It’s very difficult even though I am a very determined and goal oriented person. When I set my mind up to do something, I will normally achieve it because I am just so stubborn about personal goals that I don’t give up until I do! Yes, you will lose a lot of weight quickly, but I am not interested in giving up bread, pasta and birthday cake for the rest of my life.
What the diet advocate says: Controversial Canadian psychologist Jordan Peterson is a fan, crediting the diet for curing his daughter’s various ailments, from juvenile arthritis to depression. But it was popularised by Shawn Baker, author of the aptly titled ‘The Carnivore Diet’ – in which he describes the diet as ‘a revolutionary, paradigm-breaking nutritional strategy that takes contemporary dietary theory and dumps it on its head’.
What the expert says: ‘There have been a number of cases where GPs have said, “You’ve got IBS, go on the low-FODMAP diet”,’ says Dr Megan Rossi (@theguthealthdoctor). ‘The only support they give you is a printout with a limited explanation of the diet from the internet. I’ve had clients come into my practice who’ve been given a list of 10 “friendly” foods to survive on, which is nutritionally dangerous.’
I suffered through a year on 20 grams of carbs per day and it was the worst year of my life. Yep, I lost weight, but at my current weight of 130 lbs and eating 30 carbs per meal and remaining in a prediabetes state for 15 years, I am healthy AND happy now. None of us know the long term effects of most of what is offered to us…medications, diet drinks, processed foods, restrictive diets. The point I was trying to make was eating healthier, more natural foods will be better in the long run, I believe we all have the common sense to agree on that, even if we can’t agree on how many carbs we will eat!

Popularized by the documentary Forks Over Knives, the Ornish diet is a low-fat, plant-based diet plan based on whole grains, vegetables, fruits, and legumes. It's based on a lacto-ovo style of vegetarianism, allowing only egg whites and nonfat dairy products. It's packed with vitamins, fiber, and lots of filling plants to keep you satiated. Some studies have shown it can reverse heart disease and have beneficial effects on other chronic health conditions. (BTW, there is a difference between a vegan diet and a plant-based diet.)
The ketogenic diet tries to bring carbohydrates down to less than 5 percent of a person’s daily caloric intake – which means eliminating most grains, fruit, starchy vegetables, legumes and sweets. Instead, it replaces those calories with fat. That fat is turned into ketone bodies, which are an alternative energy source: besides glucose derived from carbohydrates, ketones from fat are the only fuel the brain can use.
There are many physiological reasons for eating enough carbohydrates throughout the waking hours to maintain a steady blood glucose level…a couple of important reasons are to minimize the hepatic release of glucose (from the liver) and to help prevent hypoglycemia which can be very dangerous and lead to hypoglycemic unawareness over a short period of time. Each person is different of course..if you aren’t taking insulin, or pills that lower your blood glucose levels, you may not have to worry about low blood sugars. The reality is, most people with diabetes do; it can be very dangerous for some to not get enough carbohydrates at each meal.
But DASH—which stands for Dietary Approaches to Stop Hypertension—is far from a fad diet. Created by the National Heart, Lung, and Blood Institute (NHLBI), the DASH Diet is designed to improve health in people with high blood pressure, a.k.a. hypertension. (In the U.S., one out of every three adults has high blood pressure, according to the Centers of Disease Control and Prevention.) U.S. News & World Report has named the DASH Diet the best overall diet for the past eight years.
What the expert says: ‘This is something that is used for athletes as part of their training. While it can lead to weight loss, carbohydrates are an energy source for the body, and restricting them can lead to headaches, fatigue and difficulty concentrating. You would be better to find the level of carbohydrates your body needs by eating normal portion sizes and a balance of all food groups.’
The purpose of this study was to evaluate the effects of a low-carbohydrate, ketogenic diet (LCKD) in overweight and obese patients with type 2 diabetes over 16 weeks. Specifically, we wanted to learn the diet's effects on glycemia and diabetes medication use in outpatients who prepared (or bought) their own meals. In a previous article, we reported the results observed in 7 individuals [10]; this report includes data from those 7 individuals along with data from additional participants enrolled subsequently.

Advocates for the diet recommend that it be seriously considered after two medications have failed, as the chance of other drugs succeeding is only 10%.[9][30][31] The diet can be considered earlier for some epilepsy and genetic syndromes where it has shown particular usefulness. These include Dravet syndrome, infantile spasms, myoclonic-astatic epilepsy and tuberous sclerosis complex.[9][32]
U.S. News’s Best Diets rankings are put together by a panel of nutritionists, dietary consultants, and doctors specializing in diabetes, heart health, and weight loss. Each member of the panel scored all 41 diets in seven different areas, including how easy they are to follow, how well they protect against chronic disease, and how likely it is that followers will actually lose weight and keep it off.
Although many hypotheses have been put forward to explain how the ketogenic diet works, it remains a mystery. Disproven hypotheses include systemic acidosis (high levels of acid in the blood), electrolyte changes and hypoglycaemia (low blood glucose).[18] Although many biochemical changes are known to occur in the brain of a patient on the ketogenic diet, it is not known which of these has an anticonvulsant effect. The lack of understanding in this area is similar to the situation with many anticonvulsant drugs.[55]
Kamut is an ancient grain native to the Middle East that is an excellent source of heart-healthy omega-3 fatty acids, protein, and fiber, while simultaneously being low in calories. In fact, a half-cup serving of the stuff has 30 percent more protein than regular wheat and just 140 calories. What’s more? A study published in the European Journal of Clinical Nutrition found that eating Kamut reduces cholesterol, blood sugar, and cytokines (which cause inflammation throughout the body). Kamut’s ability to stabilize blood sugar and reduce inflammation make it a great weight loss staple, especially if it is used in place of nutritionally lacking refined grains.
WH verdict: It’s still a diet by any other name, but props to Weight Watchers for acknowledging that there’s more to being healthy than ‘weight’. The new platform really does consider all aspects of wellness. And with plans to partner with Alexa and Google Assistant to help track your progress, WW could be to 2019 what Weight Watchers was to the early noughties.

The remaining calories in the keto diet come from protein — about 1 gram (g) per kilogram of body weight, so a 140-pound woman would need about 64 g of protein total. As for carbs: “Every body is different, but most people maintain ketosis with between 20 and 50 g of net carbs per day,” says Mattinson. Total carbohydrates minus fiber equals net carbs, she explains.

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