Best and Worst Diets Ranked by Purpose, Efficiency and Objective

There are estimated to be more than 40,000 diet and weight-loss related books on sale throughout the year and hundreds of diets. Many of these make various claims for weight loss, heart health and general well being.

It is hard for people who want to lose weight and generally improve their health by changing their diet to know what will work for them. Every year various list are published from surveys of the evidence from scientific publications and dieticians throughout the world. 

This article summarises the results from the most recent evaluations to help you choose a diet. The general criteria used to assess the various diets are:

A recent survey of the 230 members of the Dietitians Association of Australia was conducted, which asked them to list the three diets or nine popular diets they rated as the worst. The overall worst diets were: 

The Lemon Detox Diet

This diet is basically 10 days of starvation that involves a laxative tea, salt water intestinal flushes and drinking a mixture of lemon, water, maple tree syrup and cayenne pepper. This diet cuts core nutrients and is a major health risk.

The Acid and Alkaline Diet

This diet is based on the idea that excessive acid in the body is very unhealthy. Acidic foods include most fruits and vegetables, dairy, most meats, alcohol and caffeine . These foods are replaced with alkaline foods such as green, leafy vegetables, bananas and oatmeal. The dieticians were concern that many of the foods eliminated were really healthy and there was no real scientific justification for elimination of acid foods, and that this would help weight loss.

The 'Six Weeks to OMG' Diet

This diet recommends black coffee for breakfast to stimulate the breakdown of fat and the elimination of fruit because of fructose. This diet appeared to have no scientific foundation and was regarded by the dieticians as outrageous and amongst the worst diets.

U.S. News organisation in America regularly evaluates and ranks popular diets to find the best and the worst. A panel of health experts are asked to conduct research for each of the diets by evaluating scientific research and other news sources. To be given a top-ranking, diets have to be nutritious, safe, relatively easy to follow and with evidence that they are effective for weight loss, and help to control diabetes and reduce the risk of heart disease.

The panel of experts scored each of the diets on a ratings scale of 1 to 5 for the various measures which were compiled into average ratings (1-5) for each or the diets for seven criteria measures: Long-Term Weight Loss, Short-Term Weight Loss, Ease to Following, Nutrition balance, Safety, Benefits for Diabetes, and Benefits for Heart Health. The overall rating of the diets was calculated by averaging these ratings after apply various weights.

A summary of the principles applying for each of the diets is shown below as well as the various ratings:

The Worst Ranked Overall Diets

Best Overall Diet

The Best Diets for Various Specific Purposes are Shown Below


Best Diet for Quick Weight Loss

Best Diet for Long-term Weight Loss

Diets that are the Easiest to Follow

Best Nutrition Diets

Diets with the Best Safety

Best Diets to Assist Diabetics

Best Diets for Improving Heart Health

Best Plant Based Diets

Average Diet Ratings for Various Purposes

Diet  
Overall  
Quick Weight Loss  
Steady Weight Loss  
Easy to Follow  
Nutrition  
Low Sugar  
For Heart  
Plant Based  
Anti Inflammatory Diet
3.3
2.6
2.6
2.7
3.4
3.4
3.6
3.3
Atkins Diet
2.3
4.0
2.5
2.3
1.8
2.5
2.1
 
Biggest Loser Diet
3.6
4.1
2.9
2.9
3.8
3.6
3.5
 
DASH Diet
4.1
3.2
3.0
3.1
4.7
3.6
4.3
 
Dukan Diet
2.0
3.0
2.0
1.5
1.9
2.0
1.7
 
Eco-Atkins Diet
2.9
3.8
2.5
2.1
2.8
2.5
3.3
2.9
Engine 2 Diet
3.0
3.4
2.9
1.6
2.7
3.5
3.9
3.0
Flat Belly Diet
3.2
3.1
2.3
2.7
3.5
2.8
3.2
 
Flexitarian Diet
3.8
3.4
3.3
3.3
4.0
3.5
3.8
3.8
Glycemic-Index Diet
2.9
2.8
2.2
2.1
3.1
2.7
2.3
 
Jenny Craig Diet
3.7
3.8
3.2
3.6
4.0
3.0
3.2
 
Macrobiotic Diet
2.7
3.1
2.5
1.7
2.5
3.1
3.2
2.7
Mayo Clinic Diet
3.9
3.3
2.9
3.1
4.3
3.5
3.6
 
Medifast Diet
2.7
3.5
2.0
2.4
3.1
2.6
2.7
 
Mediterranean Diet
3.9
3.0
2.9
3.3
4.4
3.4
4.0
3.9
Nutrisystem Diet
3.2
3.2
2.3
3.1
3.7
2.7
2.4
 
Ornish Diet
3.6
3.1
2.8
1.9
3.8
3.5
4.6
3.6
Paleo Diet
2.0
2.1
1.7
1.7
2.0
2.1
2.0
 
Raw Food Diet
2.3
3.7
3.3
1.1
2.1
2.6
2.8
2.3
Slim-Fast Diet
3.3
3.4
3.2
3.2
3.4
3.2
2.8
 
South Beach Diet
3.0
3.7
2.3
2.8
3.2
2.5
2.9
 
TLC Diet
4.0
3.2
2.8
3.0
4.6
3.2
4.5
 
Traditional Asian Diet
3.5
2.9
2.7
2.8
3.9
3.2
3.3
3.5
Vegan Diet
3.0
3.4
3.3
1.7
2.8
3.5
3.9
3.0
Vegetarian Diet
3.5
2.9
2.9
2.7
3.7
3.4
3.6
3.5
Volumetrics Diet
3.8
3.6
3.2
3.2
4.2
3.4
3.5
 
Weight Watchers Diet
3.9
4.0
3.5
3.7
4.1
3.1
3.4
 
Zone Diet
2.9
3.0
2.3
2.2
3.2
2.3
2.8
 

Summary of the Key Aspects of Popular Diets

Diet
Features
Anti-Inflammatory Diet
This complicated diet is based on a daily intake of 2,000 to 3,000 calories, with 40- 50% from carbohydrate, 30 %from fat, and 20-30% from protein.
Atkins
This high protein, low carb diet works well for short-term weight loss but has significant safety and nutrition concerns in the long term.
Biggest Loser Diet
Is a fad diet based on the TV series based on a special food pyramid, and heavy exercise for sweating out calories.
DASH Diet
DASH was developed to fight high blood pressure and has good nutrition, good safety, low sugar, and supports heart health. It is a calorie control diet for your age and activity level.
Dukan Diet
This diet works well in the short term but it's too restrictive, with many of rules, and little evidence of long-term success. It includes various phases involving pure protein and in the maintenance phase you can eat anything you want.
Eco-Atkins
A more healthy version of the Atkins diet, but very restrictive and =hard to follow. Diet has 30% percent of daily calories from plant proteins, 45% from plant fats, and 25 percent from carbohydrate.
Engine 2 Diet
This is essentially a vegan diet with processed foods and vegetable oils banned.
Flat Belly Diet
This diet is based on using Monounsaturated fatty acids, or MUFAs, promote fullness and preventing overeating, by having one serving with every meal. Daily food intake is restricted to 1,600 calories.
Flexitarian Diet
Emphasizes fruits, whole grains, vegetables and protein from plants, is generally a healthy and smart choice. It is nutritional complete, easiness to follow, and good for long-term weight loss. Its about controlling five food groups to your diet using Breakfast 300 calories, lunches 400, dinners 500, snacks 300 for a total of 1,500 calories.
Glycemic Index Diet
This diet distinguishes between good carbohydrates and bad ones. You fill up on food with low GI carbs (<55 and under), eat moderate amounts of carbs (56 to 69), and rarely eat high-GI carbs (> 70 and up). The GI index only ranks foods containing carbohydrate, so how much meat, fish, and poultry you eat depends on you.
Intersystem
This diet focuses on mandatory fruits, protein, veggies and dairy products to supplement the Nutrisystem's packaged meals.
Jenny Craig
Is based on a personalized meal and exercise plan, with calorie targets of, 1,200 to 2,300 calories per day.
Macrobiotic Diet
The many variants of this diet are essentially vegetarian and emphasize natural, locally grown organic whole foods. Whole grains such as brown rice, barley, rye, oats, buckwheat and lost of vegetable sand fruit are included.
Mayo Clinic Diet
Focused on calories and changing 15 key eating habits, but no food group is completely off-limits.
Medifast
This diet has six meals a day, five of which are the 100-calorie Medifast products such as a shake or snack bar. The other meal consists of lean protein (5-7 oz) and 3 servings of non-starchy vegetables.
Mediterranean Diet
Focuses on fruits and vegetables, olive oil, fish, whole grains, beans, nuts, legumes, olive oil, and herbs and spices; eating fish and seafood at least a twice a week; enjoying poultry, eggs, cheese, and yogurt in moderation; red meat only rarely.
Ornish Diet
It is nutritionally sound, safe, and very heart-healthy, but it has severe fat restriction that many people find difficult. Food is categorized into five groups from most healthy (group 1) to least (group 5) healthful. It also has exercise and stress management recommendations.
Paleo Diet
This diet is based on a simple premise only eat what cavemen would have eaten. It excludes all processed food as well as refined sugar, legumes, dairy and grains. It includes lots of meat and whole fruit and vegetables.
Raw Food Diet
This diet is effective but hard to follow long term as it required dedication and commitment. Typically, about 75-80% of what you eat will be plant-based foods, raw or only warmed. Most followers are vegetarian. The diet includes lots of fresh fruit and vegetables, grains, sprouts, nuts, pulses seeds, and nuts, as well as extra-virgin olive and coconut oils.
Slim-Fast
This is a 1,200 calories per day diet with structures: three snacks; two Slim-Fast meal replacements; one 500-calorie meal you prepare. It is well suited for losing weight fast - 20 pounds in 8-10 weeks. It is hard to stick to.
South Beach Diet
The diet has 3 phases based essentially on replacing bad fats with good ones and bad carbohydrates with good ones. You can eat three meals a day, one high-protein dessert and two snacks.
TLC Diet
Therapeutic Lifestyle Changes, or TLC, is a very solid diet that is very healthful, complete, safe diet based on a target calorie level, reducing saturated fat to less than 7 percent of daily calories by be eating lots of fruits, vegetables, whole grains, low-fat or nonfat dairy products, fish, and skin-free poultry.
Traditional Asian Diet
Is based on an Asian diet pyramid that revolves around daily consumption of rice, noodles, breads, millet, corn, and other whole grains, along with fruits, legumes, vegetables, nuts, seeds and vegetable oils. Fish and shellfish (or dairy) are optional. Eggs and poultry can be eaten once a week and red meat once a month. Six glasses of water or tea each day are required per day.
Vegan Diet
Overall, there was concern about nutrient deficiencies with this diet, which is not necessarily low calorie or low fat. It fruits, whole grains, vegetables, leafy greens, seeds, nuts, and legumes.
Vegetarian Diet
Various options are available depending on whether eggs, poultry and dairy products are consumed. Fruit and vegetables dominate
Volumetrics
Is based on an eating plan based on cutting the energy density of your meals, and appetite suppression fight hunger, with food in four groups.
Weight Watchers
Weight Watchers is a smart, effective diet, nutritionally sound and safe, with group support, lots of vegetables, fruits and whole foods. It allows occasional indulgences. It is based on a PointsPlus target system for selecting foods.
Zone Diet
This diet is hard to follow as you have to structure every meal according to a specific macro-nutrient thresholds. The diet has a threshold of daily calories set at 1,200 for women and 1,500 for men. You eat three meals and two snacks daily. Each meal should contain 40 percent carbohydrate, 30 percent healthy fat and 30 percent protein.




Vegetarian Food Pyramid
Vegetarian Food Pyramid. Source: https://commons.wikimedia.org/wiki/File%3ALoma_Linda_University_Vegetarian_Food_Pyramid.jpg
Vegetarian Food Pyramid - Second Version
Vegetarian Food Pyramid - Second Version. Source: https://commons.wikimedia.org/wiki/File%3AVegan_food_pyramid.svg
Mediterranean Food Pyramid
Mediterranean Food Pyramid . Source: Public Domain