COMPARING ATKINS, ORNISH, WEIGHT WATCHERS, AND ZONE DIETS.

Many popular diets exists, many departing substantially from mainstream medical advice.  I will review the popular ATKINS, ORNISH, WEIGHT WATCHERS, AND ZONE DIETS.

The Atkins diet aims to began with less than 20g of carbohydrates daily, with a gradual increase toward 50g daily.  The Zone diet keeps their diet at a 40-30-30 balance for percentage calories from carbohydrates, fat, and protein, respectively.  People on Weight Watchers keep total daily “points” in a range determined by current weight.  Each “point” is about 50 calories, and most aim for 24-32 points daily.  The Ornish diet is a vegetarian diet containing 10% calories from fat. 

A study was done taking 160 participants randomly divide in either Atkins, Zone, Weight Watchers, or Ornish diet groups and followed for 12 months.  The changes from baseline calories to the end of 12 month calories in each is as follows:
   
                                  Baseline    12 mo
Atkins                         1898        1886
Zone                           2059        1757
Weight Watchers        2056        1832
Ornish                        1947        1819

The highest discontinuation rates were seen in the Atkins and Ornish diet groups, reporting that these diets were too extreme.  After 1 year, all 4 groups show weight loss, without significant differences between each.  In each group, about 25% of participants lost >5%, and 10% lost >10%.  Each group showed reduced total cholesterol, with the Zone (-10.1) and Ornish (-10.8), showing the highest, and Atkins (-4.3) having the least change.  HDL (the good cholesterol) had the same increase in Weight Watchers, Zone, and Atkins (3.4), with the Ornish having a decrease (-0.5).  Blood pressure decreased about the same in Weight Watchers, Zone, and Atkins, but had an increase in the Ornish group.  Although slight, the Zone diet seems to have the most cardiac protective effects.

Weight loss was similar in all diet groups, not necessarily because of the type, but rather the amount of food was decreased in all.  Another study divided people into 4 groups:

High carbohydrates, low protein, low fat
Low carbohydrates, high protein, low fat
Low carbohydrates, high protein, high fat
About equal in carbohydrates vs protein vs fat.

Each group had about the same weight loss.  Each group also consumed 500 calories per day less than they normally did.  Point-in-case, It not necessarily the food you eat, but how much you consume.  Most will see significant results of diets consisting of 1500 calories or less per day.
Proteins take longer for the body to digest and absorb than either carbohydrates, or fat.  Actually carbohydrates are digested the quickest, leading one to eat more carbohydrates to feel full.  Because proteins take longer to process, the body senses satiety quicker and stays full longer.


 I have previously mentioned this in the post:
http://dochealthmd.blogspot.com/2015/01/lose-1lb-per-week-with-these-protein.html

One study placed participants on a high-protein diet consisting of 20% fat, 50% carbohydrate, and 30% protein.  With greater satiety by the high protein diet, the subjects ate about 450 fewer calories per day and lost about 1 lb. per week (11 lbs in 12 weeks).

This diet is closest to the Zone diet, and a sample day's breakfast could be a cup of cooked oatmeal with a tablespoon of walnuts, a small handful of blueberries and 1/2 a scoop of protein powder. Your lunch could be a small tuna and light mayo sandwich accompanied by an apple and dinner a piece of baked cod with 1/2 cup of black beans and a mixed salad with olive oil. Between meals have snacks like a boiled egg and a piece of fruit, a small pot of cottage cheese with pineapple and cashews, or 1 ounce of pre-cooked meat with vegetable sticks and hummus.  I have listed recipe sources below.