Low Carb Diet Comparison - Which One is Right For You?

If you are an occasional dieter or a perennial dieter, whether you want to lose a few pounds or maybe a lot more than a few you have probably heard about low carb diets. You have also probably heard that very low carb diets are the fastest way to lose weight.  While this is true - are they right for you and if so which one is best? You have many low carb diets to choose from such as the rock star Atkins, the Keto Diet, new kid on the block Paleo Diet, the South Beach Diet and the barely low carb Zone Diet. Sure there are others, but these are the more well know and followed. They also give us a decent variety at least in as much as low carb allows.

Ketogenic Diets

Ketogenic diets are diets that cause your body to break down fats to use as its primary fuel source. The idea is that carbohydrates particularly simple carbs induce a large insulin release to uptake all the sugar.  This leads to increased fat storage and concomitant hypoglycemia which increases cravings. On ketogenic diets fat and protein consumption is increased. Both nutrients are satiating and both especially in the case of fat do not cause an insulin release response.  On a ketogenic diet you consume less than 50 grams of carbohydrate per day (all sources minus fiber and sugar alcohols) compared to the standard recommended diet of 225-325 grams/day based on 2000 calories per day. This restriction in carbohydrates leads to glycogen depletion causing the metabolism to enter into a state of nutritional ketosis in which stored fat is mobilized and broken down into ketones bodies as a fuel source. The fact that the body is inefficient at this leads to dramatic fast weight loss. Add that another study has shown that high fat-low carb diets induce an increase in metabolism, burning as much as 250-300 additional calories per day.

There are many similarities to the ketogenic diets discussed above, mainly restricting carbohydrates, but there are also differences. Let’s discuss them individually.

Atkins Diet

Veal chops and vegetables

This is the rock star of low carb diets because it is the best known and most adhered to diet practiced by celebrities and non-celebrities alike. Atkins allows high levels of saturated fats often using whole cream, cheeses and fatty meats to up the fat ratio. There are 2 versions of the diet for weight loss the 20 and the 40 carb version. This refers to the amount of carbs you can consume during the first phase (induction) of the diet where you convert to a ketone metabolism. This phase generally lasts for 2 weeks, but some choose to stay here longer. Next you go on to Phase 2 or re-balancing. Here you can add acceptable foods in 5 gram increments and continue somewhat slower weight loss. This will lead you to Phases 3 and 4 which are the bridge to and the maintenance phase. By now with experience you should know how many carbohydrates your body can tolerate without gaining or losing weight.

Some allowed foods:

·         Beef (steak, hamburger)                                 Eggs                   

·         Pork                                                                  Bacon

·         Fish (salmon, tuna, halibut)                            Fowl

·         Cheeses                                                           Whole cream

·         Oils                                                                    Nuts and nut butters

·         Butter, mayonnaise                                          Low sugar dressing

·         Spinach, lettuce, broccoli,                              Asparagus, cauliflower

·         Peppers, summer squash                               Tomato, kale

This is just a partial list for example only.

Unacceptable foods:

·         Starches, potatoes, corn, rice                        Pasta, breads

·         Root veg (turnips, beets, carrots                  Watermelon, pineapple, banana

·         Sugary drinks, sugary snacks                        Fruit juices

Many of these are allowed in later phases in small amounts.

Keto Diet

The Ketogenic diet is in some ways the granddaddy of low carb. Versions have existed since 500 BC. In the 1920’s the Ketogenic Diet was used to successfully treat epilepsy and has been used to fight cancer by robbing it of its favorite food…sugar. Ketogenic diets are currently being tested on Alzheimer’s.

This diet differs from Atkin’s in a couple of ways. Dairy and alcohol are not allowed here whereas they are allowed in the Atkins diet. This diet is 75-80% fat compared to Atkin’s at about 65% in phase 1. This diet keeps carbohydrates at 5% whereas Atkins allows incremental increases in carbohydrates up to 15-20% in subsequent phases allowing for a more rounded easier to follow plan.

Unacceptable foods:

·         All grains                                                           Milk

·         Legumes                                                           Refined oils

·         Sodas, Juices                                                   Artificial sweeteners

·         High carb fruit                                                   Soy

Paleo Diet

The Paleo Diet is the newer kid on the block with possibly the oldest roots. This diet looks to follow what was believed to be the diet that developing early man consumed.  You essentially eat only foods that were available to man back then. We are talking about 10,000 to 1 million years ago, so no farmed or domesticated food sources.  Meats must be grass fed, eggs and poultry cage free. The focus is on leaner meats, unsaturated fats, and substantial fruits and vegetables. This diet can range from very low carb to moderately low carbohydrate (P 19-35%, F 28-47%, C 22-40%) depending on the individuals preferences.

Unacceptable foods:

·         Grains (wheat, barley, rye, etc.)                  Artificial sweeteners

·         Legumes (beans, peas, lentils)                     Dairy (milk, cheese, yogurt)

·         Sugar                                                                Processed foods

South Beach Diet

Man on weight loss scale and tape measure

This diet is a strong comer as it has garnered quite a bit of press and adherers. Created by a celebrated cardiologist this diet is supposed to be a no brainer when you use their pre-packaged foods. There is meant to be no counting of calories or macros, when you eat according to the plan you are in the correct healthful nutrient level.  With a little more work you can also follow without purchasing their foods. This is a 3 phase diet with the first phase being the strictest. Like the Atkins Diet 40 the 1st phase is 2 weeks long and designed to transition your metabolism to a ketone burning machine. Carbohydrate intake at this point is about 40-50 grams/day. This diet focuses on low fat protein sources, but allows the use of processed oils and artificial sweeteners. In phase 2 you slowly add more servings of fruit, veggies and whole grains. Continue in this phase until you lose all the weight you want (1-2 lbs. week) then go to phase 3. Phase 3 is about maintenance, similar to the end of phase 2, but with the occasional cheat meal.

Allowable foods:

·         Whole grains, fruit, (phase 2 and 3)            Processed oils, artificial sweeteners

Unacceptable Foods:

·         Fatty meats                                                      Whole milk, full fat cheese, butter

The Zone Diet

Though technically not a ketogenic diet the Zone does limit carbohydrate intake to about 40% of calories. Officially listed as a 40/30/30 diet, 30% of nutrients come from protein and another 30% from fat. This diet does not depend on ketosis for weight loss. The Zone claims to be an anti-inflammatory diet and hormonal regulator. I included it as a lifestyle choice that is easier to adhere to, but works better for maintenance and slower weight loss. To lose weight on this diet you must regulate calories in the form of blocks. Each food block includes fats, proteins and carbohydrates. There are prepackaged foods that aid in keeping calories in check, but are not required. Food options include low glycemic (low sugar) fruits and vegetables, lean proteins, and unsaturated fats. Choices are similar to foods in the Mediterranean Diet. No foods are banned, but some are not recommended.

Foods to avoid:

·         High fat meats                                                 Starches (corn, potatoes)

·         Refined carbs (breads, cereals)                   Processed foods


Though many of these diets are meant to be lifestyle diets they are also often used as short term diets for quick weight loss, maybe in the 10-30 pounds range. In many cases people will cycle on and off depending on weight fluctuation going back on when they gain a few pounds. To garner the full health benefits your diet should really be a lifestyle, so I recommend picking the diet you feel you can more easily stick to, maybe a diet that allows the occasional deviation (cheat meal). Consider also what foods are not acceptable for instance some of these diets allow legumes and dairy or saturated fats while others don’t.  You want to adhere to the diet you pick as closely as possible for best results. My personal diet (the Ultimate Health Diet) starts out similarly to the first 2 phases of Atkins, but then becomes more like the Zone with a little less carbs, a bit more saturated fat and no processed oils. It is easy for me to adhere to and keeps me on target.  

You can get more information on specific diets by following the licks below.

If you are on medication, have kidney disease or another metabolic or health condition you should check with your medical professional first before starting a carbohydrate restrictive diet. This type of diet can impact the dosage requirements of medications for diabetes and liver disease among others.


Ncbi.nim.nih.gov/pubmed/19049574 – History of the Ketogenic Diet

Ncbi.nim.nih.gov/books/NBK537084/#article-38819.s4 – Low Carbohydrate Diet

Healthline.com - The Atkins Diet-Everything You Need to Know

Healthline.com - The Paleo Diet – A Beginners Guide

Healthline.com – The Ketogenic Diet – A Detailed Beginners Guide

Atkins.com – Atkins: Low Carb Diet Plan

Mayo Clinic.org – The Paleo Diet: What it is and why it’s so popular

Drax.com – Is the South Beach Diet Still Legit

Southbeachdiet.com – How the South Beach Diet Works

Healthline.com – The Zone Diet: A complete Overview

Zonediet.com – The Zone Diet – Dietary Program to reduce inflammation