05 July 2015 ~ 5 Comments

Fasting Working Outs For Fat Loss, Ketosis + LoCarbs Diets


Last March I read this article about fasted workouts and thought it made sense. I tried it a few times, but no consistently. Then more recently, in 2016, I have been hearing about intermittent fasting, which ties into those attempting to implement Ketosis into their nutrition regimen. Ketosis is different than than the so-called Paleo Diet, because it endorses the use of high fat, moderate protein and little, if any, carbohydrates including fruit. The idea is that you purge your body of most carbs and thus allowing your workouts and metabolism to “burn away” your fat and not your muscle or remaining carbs. The Paleo Diet, as I understand it, encourages a more even balance of protein and fats, and once again, consumption of few carbs in the form of grains. Fruits are OK with the Paleo plan.

Below are varying opinions on both intermittent fasting and  high carb vs. low carb plans.

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Cycling Weekly

This article from Cycling Weekly endorses fasted training, something I have not done much of, but believe could be a benefit.

Among other things, this author says:

  1. Keep intensity low
  2. Try fasted riding
  3. Perform intervals if time is short
  4. Get your recovery routine sorted

I don’t understand as point #1 and #3 are in conflict. When I do intervals, my intensity is high—isn’t that the whole point of doing them?

Otherwise, I link this article is very useful.

Dr. Mike Video

April 2016 Update: Here is an interesting video by Dr. Mike VanDerschelden, a chiropractor working for this firm in California about intermittent fasting. Essentially he says to stop eating at 8:00 p.m. at night and then in the morning only consume Bullet-proof Coffee (coffee with coconut oil and butter added). Shortly before noon do a fasted workout for 20-30 minutes (high intensity interval training or HIIT preferred; at the end of your fast). Then, immediately after your workout, eat your lunch at noon, skipping a formal breakfast. This provides a fasting period of 16 hours. He claims this should bring body into a state of ketosis, i.e. it burns fat and not glycogen.
In the past I have always snacked throughout the day, but that means I was not giving my body a chance to “eat away” fat stores. I have also heard that we might consider eating our last meal four hours before sleeping. In my case, that would mean eating no later than 7:00 p.m. and retiring at 11:00 p.m.

Ben Greenfield Podcast

This podcast by Ben Greenfield (Dec. 2015) is worth listening to (or read the transcript) as he is a big supported of the Ketosis movement (which includes intermittent fasting), not just for body-builders, but for all athletes including endurance types.

The Keto Diet Blog on Intermittent Fasting

This is one of the best sites regarding Ketosis which I have seen. This page endorses the fasting concept.

A French Study Endorses Hi-Carb
Before Workouts & Lo-Carb Afterwards

This new study as found on the Road Bike Rider website, was published in April of 2016. It says “They suggest that athletes should eat their carbohydrates during the day and then restrict carbohydrate intake after their intense training session in the afternoon and before they go to bed at night.” They also suggest that the following morning, after a hard cardio workout, to do a morning recovery workout at an easy pace: “Before your morning recovery workout, drink only water, black coffee or tea (no cream or sugar) and, if your muscles feel heavy and tired, you can eat a single fruit such as an orange. Do not drink fruit juice…An overnight carbohydrate fast after your alternate-day intense workout keeps your muscles low in their stored sugar. Then exercising muscles depleted of their stored sugar teaches your muscles to burn more fat and less sugar, so you keep sugar in your muscles longer, and that makes you faster and stronger and gives you greater endurance.”

Personally, the above regimen sounds very logical to me and I plan to try it for a few weeks.

CTS / Train Right

This page of the respected Train Right site has a contrary view to working out on an empty stomach to lose weight!
Also review this article on the same site about low carb training. It says “This somewhat logical consequence of training with low CHO (carbohydrate) availability has led to the idea of Train Low/Race High and subsequently Train Low/Train High methods where you do lower-intensity endurance rides with low CHO and prepare to perform interval workouts or race with high CHO availability.”

Eric Heiden, M.D. Recommends Well-rounded Diet

(Five-time Olympic gold medalist)

From the 2008 book Faster Better Stronger: “Modern civilization, your work schedule, and your other obligations artificially dictate that you divide your food intake into three meals a day, but biologically, your body does better when you eat more often—about every three to four hours.” ( p.80) “Studies show that if you wait longer  than five or six hours to eat, you consume disproportionately larger meals.” (p. 81) Speaking of supper, he says “….divide you plate in quarters, two-quarters should be dedicated to vegetables, one-quarter to lean protein and one-quarter to carbohydrates. Your carbs should be whole grain and roughly a half to one cup in size. A serving of protein for the average adult is about the size of a deck of cards—about three ounces of meat.” (p. 86)

The Book Racing Weight Does Not Endorse
Low Carb Diets or Fasted Workouts for Endurance Athletes

This soon-to-be classic book, published in 2009 by Matt Fitzgerald, is designed for any endurance athlete, whether it be a cyclist, rower, skier or runner. It discusses how to get your optimum weight based on your particular sport.
He says “Atkins advocated a carbohydrate intake of no more than 40 grams per day, which is equivalent to less than 10 percent of total calories of most people. That’s extreme when you consider than mainstream nutrition experts believe that the nervous and immune systems of the average person cannot function properly on a diet that provides fewer than 150 grams of carbohydrate per day.” “The rationale for adopting a high-protein diet is that protein is the most satiating macro-nutrient, so people tend to eat less overall when they eat a lot of protein.” (p. 112) “My own view is that the evidence indicates that carbohydrate intake should be proportional to the individual athlete’s training load.” (p. 116) “The typical endurance athlete gets 30 to 35 percent of her daily calories from fat—substantially more than the minimum.” (p. 120) On page 127 he has a chart that indicates that the optimal macronutrient range for an endurance athlete should be in the range of 40–80% of carbohydrates, 20–40% of fat and 10–25% of protein.

“There is abundant research showing that endurance performance is compromised in the fasted state (more than 12 hours after the last meal). ( p. 145) “There is a need for more formal studies of the effects of intermittent fasting on competitive endurance athletes. The findings of these studies are not likely to make you see conversion to intermittent fasting of any kind! Sure, athletes do lose weight and body fat during Ramadan…In addition to impairing endurance performance by reducing muscle and liver glycogen and blood glucose levels, intermittent fasting is likely to sabotage performance further by interfering with recovery from training.” (p. 146)


I have only tried the full-on intermittent fasting and Ketosis regimen for about a week so far (April 2016) and did not lose much, if any weight. I do believe that not eating much after 7 or 8:00 p.m. is beneficial for weight management though and practice that today, including a late breakfast or brunch at 10 or 11:00 a.m. (unless a early morning workout is scheduled and then I eat breakfast earlier). Perhaps I have not given the Ketosis concept enough time to know if it is feasible for me. Most of my friends and family that are using this concept are body-builders and do little endurance training. I have tried some fasted interval (HIIT) workouts (as per the Dr. Mike video above) on a mostly empty stomach and have had lackluster results. I just felt super weak and could not get my heart rate up. The book Racing Weights says “When you wake up in the morning your liver is approximately 50 percent glycogen depleted due to having powered your nervous system as you slept.” (p. 134) I wonder if the Ketosis concept, which is NOT the same as the Atkins high-protein diet (it is high-fat, moderate to low protein) is too new and most experts have not had time to give it a fair evaluation. Or perhaps it more suited to the body-builder type person and not for aerobic-based endurance athletes.

For me, the best way to lose weight is to eat very lightly in the evening after a hard cardio day. I still consume a protein smoothie right afterwards and some 60 minutes or so later eat a very light supper. I have tried to replace all the grain carbs in my diet with more some fruit, more vegetables and lean proteins such as poultry, plain no-sugar-added Greek Yogurt, cottage cheese, aged sharp cheddar cheese and a lots of nuts. (This is largely due to the fact I recently read the very compelling 2011 book entitled Wheat Belly, by William Davis, M.D.)

5 Responses to “Fasting Working Outs For Fat Loss, Ketosis + LoCarbs Diets”

  1. Roger Peskett 20 April 2016 at 4:00 pm Permalink

    A very interesting question is whether a ketogenic diet enables the endurance athlete to train her body to burn fat more efficiently. The amount of carbohydrates anyone can digest during exercise is limited, and even a lean athlete’s CHO reserves are more limited than fat reserves. In long events, the body must burn fat.
    Science Daily reports a study which is claimed to show that: “Endurance athletes who ‘go against the grain’ become incredible fat-burners”. For more detail, here is the study.
    See also the 2012 book by two of the authors of the study, Jeff Volek and Stephen Phinney: ‘The Art and Science of Low Carbohydrate Performance’.

  2. Rando Richard 20 April 2016 at 5:12 pm Permalink

    I’ll check out your links. I have heard now from several people about the Volek/Phinney book — guess I need to grab a copy. My many years, my ultrarunning friends have told me that runs (or rides) beyond three hours require ingesting more fat, not just carbs. I have done some 24-hour bike races and have focused on consuming lots of fats on those; in fact I have a list! Here it is:
    * Croissants with Nutella
    * Peanut butter & honey tortilla rolls (cut down to bite-sized chunks to fit in my top tube bag)
    * String cheese
    * Hard Boiled eggs
    * Fig newtons
    * Coconut macaroons
    * Candy covered peanuts
    * Mixed nuts
    * Macaroni salad (one of all-time favorites)
    * Peanut butter and banana bread or tortilla sandwiches
    * Chocolate milk
    * Canned chicken
    * Bananas 
    * Steamed red potatoes
    * Kirkland cashew sunflower seed clusters
    * Coconut milk
    * Pop tarts
    * Produce: pineapple, watermelon, grapes, bananas
    * Sports drinks for on the bike
    * Elite (electrolytes for on bike bottles)

  3. Roger Peskett 20 April 2016 at 6:17 pm Permalink

    I commented that the rate of intake of CHO is limited, but of course that applies to food overall, including fat. So the question then becomes, can we train the body to tap into its plentiful fat reserves more efficiently? Volek and Phinney claim that a (strict!) ketogenic diet over a number of weeks (or many months, in the study I cited) is necessary preparation to enable the body to become efficient at burning its reserves of fat.
    But your original post is mainly about reducing fat in order to lose weight, rather than burning fat efficiently in order to be able to extend athletic endurance and performance, so apologies if I am going off at a tangent here.

  4. Rando Richard 20 April 2016 at 8:13 pm Permalink

    No, it is not off tangent — I started the post with fat-loss fasting, but my thoughts have migrated to the ketosis theory, which commonly requires intermittent fasting.

  5. Roger Peskett 21 April 2016 at 1:46 pm Permalink

    Intuitively, I’d have thought that short-term intermittent fasts are less likely to change metabolism in the way than weeks-long keto-adaptation (as recommended by Volek and Phinney) might.
    A cyclist friend of mine (Larry) is enthusiastic about the ketogenic diet, and writes: “My coach has had me on it for over a year now and my wife also is keto for 6 months.. It has made a huge difference in energy on the bike, I can ride up to 100 miles now without even thinking about food..I have had testing done that shows I am running on 100% fat for energy.. it is wild! I eat between 20-50 carbs a day, most days 20 unless I am riding and then might have 50.. I would recommend it, my cholesterol is perfect, I am under a doctor’s care and doing great!”
    I found a clear and concise explanation of keto-adaptation vs. ketosis in this archived Reddit post.

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