Emily Brown

Written by Emily Brown


Could a Weight Loss Fad Diet Support a Runner’s Dietary Requirements? The Leading Plans’ Pros and Cons Explained

Many people take up running in an effort to kick-start or promote weight loss.

For those already involved in the sport, weight loss/reduction in body fat or even just a different way of eating will help them perform better.

In either situation, healthy weight loss and better eating can be a good thing with many benefits, including improved health and running times.

While the formula for weight loss is pretty simple (calories consumed < calories expended), the number of methods and plans for achieving it are extensive.

Often “fad” diets that are prominent in the media can be appealing because they promise quick results, provide the user with a ready made “plan,” and are backed by doctors, celebrities, or real life testimonials/success stories.

As runners, however, we need to be especially critical of diets because we have different energy needs than the general population to support our training and recovery.

I have reviewed and identified the import highlights of a handful of the most recent and popular marketed fad diets to help guide you.

The Atkins Diet

Overview: Based on the theory that eating too many carbohydrates leads to weight gain and that as a population, we consume too many carbohydrates.

  • Very low carbohydrate, especially in the beginning (<40 grams/day), but basically not limiting in protein or fat intake
  • Does not allow consumption of refined sugar, milk, white rice, or white flour. Limits intake of fruits, vegetables and whole grains.

How it works: A drastic reduction in the consumption of carbohydrates forces our bodies to burn stored body fat. Ketones, which are created by the breakdown of fat, are used for energy (ketosis). When the body is in ketosis, you tend to be less hungry and therefore eat less.


  • Quick and dramatic weight loss
  • Get to eat savory and highly desired foods (steak, bacon, cheese, etc.), seemingly without limits
  • Has changed over time to promote lean proteins, healthy fats, fruits, vegetables, and even some whole grains


  • Weight loss is quick, but much of that is water weight (remember that glycogen stores water with it)
  • May be lacking in a number of vitamins and minerals that are usually obtained from fruits, vegetables and whole grains
  • Does not provide nearly enough carbohydrate to support training. The body needs about 150 grams of carbohydrate each day to support normal metabolic functioning, including efficient brain functioning.
  • Ketosis can cause some negative side effects such as constipation and an unusual breath odor
  • Very difficult to stick with and does not have a good track record for maintenance of results

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Zone Diet

Overview: Diet consists of 30 percent protein, 30 percent fat, 40 percent carbohydrate. This ratio is different than a standard, food pyramid diet, because the carbohydrate level is lower, and is claimed to create a “metabolic state in which the body works at peak efficiency.”

  • Allows for a small amount of protein at every meal; limits dairy products
    Categorizes “favorable” and “unfavorable” carbohydrates
  • “Favorable” (can have a larger serving)- whole grains, most fruits, most vegetables, lentils and beans
  • “Unfavorable” (smaller servings)- brown rice, pasta, dry breakfast cereal, bread, bagels, tortillas, carrots, mango, papaya, banana, and fruit juices
  • Minimizes saturated fats and promotes olive and canola oils, avocados, and healthy nuts
  • Meals need to be regulated for size and content

How it works: This ratio of macronutrients is thought to control the body’s production of insulin, which acts to store excess calories as fat.


  • Compared to other diets, a wider range of foods are allowed
  • Promotes the intake of vitamin and mineral-rich fruits, vegetables and whole grains
  • Promotes lean proteins and healthy fats


  • Too low in carbohydrate to meet the needs of an endurance athlete
  • Can be difficult to stick to as it does take some knowledge and practice to get the ratios right
  • Not much scientific evidence to back up the claims

South Beach Diet

Overview: Very similar to the Atkins diet, but bans unhealthy fats while promote healthy ones. Also does not require user to count grams of carbohydrate and encourages the consumption of low-sugar, low-glycemic index carbohydrates.

  • Promotes “strategic snacking”– eating often throughout the day, but only enough to satisfy your hunge
  • No sugar-rich carbohydrates such as rice, potatoes, corn, sugary sweets, or alcohol
  • Diet has three phases, ranging from an almost complete ban on carbohydrate to a slow reintroduction of some “banned” foods

How it works:
Introduction phase is meant to eliminate the craving for carbohydrates, particularly the “bad” ones. When highly processed carbohydrates are digested, they cause a spike in insulin and which makes you crave more food and store the excess food as fat. By eliminating the craving for carbohydrates, you can avoid this insulin response and eat better foods in smaller amounts.


  • Diet is rich in healthy foods such as fruits, vegetables, whole grains, and lean protein
  • No major food groups are eliminated, at least when you reach phase 3 (maintenance) and is a diet that could be maintained pretty easily
  • If diet is adjusted to swap some fat calories for carbohydrates, an endurance runner could meet their carbohydrate needs


  • Much of the earlier weight loss is water weight, which could make you dehydrated and lead to electrolyte imbalance
  • Does not use specific calculations for nutrient needs based on athlete weight and training

Paleo (Caveman) Diet

Overview: Based on the theory that our bodies are genetically programmed to eat like our caveman ancestors. According to the founder, our genome has not adapted to the foods that are now typical in the Western diet, which can be inflammatory and promote chronic disease.

  • Diet is based on foods that could be hunted, fished, or gathered
  • Adapted to today’s times to include lean meat and organ meats (grass-fed), fish (wild-caught), poultry, eggs, nuts, fruit, and vegetables
  • Does not allow dairy, grains, sugar, legumes, potatoes, or processed oils (also no added sugar or salt)
  • For drinks, only allows water, coconut water, and organic green tea (no milk, coffee, or alcohol)
  • Because it is so restricted, user is advised that eating this way at least 80 percent of the time is enough to obtain the health benefits

How it works: Diets rich in lean protein and plant foods contain a lot fiber, protein, and fluids that help satisfy hunger and control blood sugar, so as to prevent weight gain and the development of type 2 diabetes.


  • Follows the current trend of most healthy diet recommendations by eating a “cleaner” diet that is rich in whole foods and low in sugar, sodium, and processed foods
  • You probably will feel a lot better after eliminating processed foods from your diet
  • Does not limit the intake of most fruits and vegetables like some other low-carbohydrate diets
  • Allows you to choose from a wide variety of foods within the food groups allowed


  • Is too low in carbohydrates for most runners due to grains and starchy vegetables restrictions
  • Elimination of certain entire food groups (dairy, grains) poses a high risk for nutrient deficiencies (especially calcium and vitamin D)
  • Diet can be very financially costly and difficult to sustain for an extended period of time

As with any diet and nutrition plan, individual responses and preferences need to be considered. However, it’s also important to consider how you plan to lose weight and maintain a specific diet if maintaining your running performance is a top priority. Hopefully, outlining some of the pros and cons of the more popular diets can help you refine your nutritional intake to lose weight, eat healthy, and maintain your training and racing goals. If you have any questions, please feel free to ask them in the comments section. If you’re really struggling with aligning your nutritional and performance needs, check out or newest nutritional services packages.

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4 Responses on “Could a Weight Loss Fad Diet Support a Runner’s Dietary Requirements? The Leading Plans’ Pros and Cons Explained

  1. Low Carb/Atkins/Paleo is viable and the cons listed are BS. You can get all the vitamins and minerals you need from animal products, if you restrict carbs and stay in ketosis you can function at a higher level than you would burning sugar, and you do lose water and need less water to function since it is not being absorbed and used to process sugars. Ever hear of Timothy Olson – low carb runner.

    • Hi Jason, thank you for your comments. Let me just say that when I wrote this article, as when I write all of my articles, I am writing from a very general perspective knowing that runners are very different- in the foods they eat, the way they burn that food for fuel, the distances they race, the intensities at which they run, etc. I understand that there is a population of runners (like ultrarunner Timothy Olson) and non-runners alike that have successfully followed a low-carb diet and have experienced many benefits from it. However I wouldn’t say that the “cons” I mentioned are “BS”- these cons may be just as real and just as applicable to many who have unsuccessfully tried low-carb diets.
      I just wanted to respectfully make a few points in response to your comments. 1) It is not true that you can get all the vitamins and minerals you need from animal products alone. You still need to incorporate fruits, vegetables, nuts, seeds, etc. to meet your body’s needs. 2) Like carbohydrate, fat also needs water to metabolize. Furthermore, in order for fat to metabolize and be used as energy, some carbohydrate must be present. 3) As I mentioned before I write from a very general perspective- more for the 5k, 10k, 1/2 marathon and marathon runners. Ultra-running is very different when you consider distance, time, pace, and thus fuel use. In ultra-endurance events, fat is a much more viable and valuable fuel, but at the cost of pace and intensity. Fat takes longer to metabolize than carbohydrate and also requires the presence of oxygen, so the intensity of the exercise must be lower and the pace must be slower. During races like 5ks or 10ks when you are running at 85-90% VO2max, carbohydrate becomes the more viable fuel source.

      • Thanks for your response.

        The only vitamins that are not available are B12 and D (which you can get from the sun) so you you are correct, you will need some plants (leafy greens work nicely). Your body does need carbs to process the fat. You can never actually get to zero carbs but if you don’t consume enough your body will break down protein to meet glycogen needs.

        Everyone is different and responds differently to different diets. I don’t suffer the side effects you list, others may. I don’t think anyone could argue that fact that the majority of Americans consume way too many carbs, especially refined carbs, and would be much healthier if they reduced their sugar intake.

        I would not recommend low carb for short distance runners (less than marathon) but I do believe that it is a healthier alternative even if you don’t run.

        I would recommend “The Art and Science of Low Carbohydrate Performance” by Volek and Phinney if anyone is curious about this subject.

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