Fad Diets Series #2 – Intermittent Fasting & Carb Cycling

As we continue our series on fad diets, we move to two of the trending fads: Intermittent Fasting and Carb Cycling.

Intermittent Fasting

Intermittent Fasting is not new but has gained momentum recently as an alternative to the traditional calorie restriction model so many have followed in the past. For men over 50 who walk that line between an ideal weight and carrying that extra ten pounds, the idea may sound intriguing.

But as with all diets (fads alike), there are advantages and disadvantages and no small amount of marketing intertwined with unending success stories. We set out to review the most current research we could find as to whether it will yield the best results for weight loss and your health.

What Is It?

For a straight up definition, intermittent fasting (IF), or intermittent calorie restriction, is a phrase for an eating pattern where you cycle between periods of eating and fasting. It’s less about the foods you eat but rather when you eat them.

There are several methods with varying names, all of which can split the day or week into eating and fasting periods. We’ll stay close to the National Center for Biotechnology Information (NCBI) details and results since this looks to be where other sources use for reference.

Alternate-day fasting: As the name implies, you alternate between feeding and fasting days with the intent of reducing your calorie intake on fasting days by drinking liquids. If this sounds too challenging, UIC researchers suggest one hearty lunch meal consisting of 500-600 (roughly 25% of daily calories for a 50+ active man) on the fast day. Non-fast days consist of your normal meals.

Does it work? Studies point to short-term (trials of 3 to 12 weeks) success rates of body weight reduction of 3%-7%, 3-5.5 kg reduction of body fat and lower cholesterol and triglycerides. (NCBI Source)

Whole-day Fasting: This type of fasting represents a substantial limiting of your calories or total abstaining from food from 24 to 36 hours, also may be known as the 5:2 diet or undertaken as a belief practice. This method may be an intense version but during the fast you can still restrict your calories to 25% as in the Alternate-day Fasting model.

Does it Work? Short-term trials of 12 to 24 weeks show a reduction of body fat and body weight from 3%-9%, and an improvement in blood lipids (lower cholesterol and triglycerides). (NCBI Source)

Time-Restricted Feeding: A popular form of intermittent fasting, Time-Restricted means you consume your daily required calories within an 8-hour timeframe, not a day range. For example, you would eat three meals; one at 1:00 pm, one at 4:00 pm, then one at 8:00 pm. The remaining 16 hours are the fasting period. (NCBI Source).

Does it work? While no long-term studies could be found, in an 8-week test, 34 males either were placed in a traditional diet group or followed the time-restricted regimen listed above. The TRF group showed a decrease in fat mass (as compared to a normal diet group) but both kept muscle mass and maximal strength.

Benefits to Intermittent Fasting

In this referenced 2016 NCBI study, researchers state that a growing body of evidence indicates intermittent fasting represents a useful tool in improving health in the general by:

• Improving blood lipids (Cholesterol and triglycerides).
• Improving glycaemic control (blood sugars).
• Reducing circulating insulin.
• Decreasing blood pressure and inflammatory markers.
• Reducing fat mass even during short periods.

They attribute these benefits to fasting contributing to the metabolic and cellular processes to stress, lipolysis (breakdown of lipids) and autophagy (the natural destruction of unnecessary cellular components).

Disadvantages of Intermittent Fasting

While we couldn’t find precise studies on the disadvantages of fasting, there was ample opinion and medical papers that cautioned against ignoring a few basic nutritional facts:

• People with eating disorders, who are underweight, pregnant, or diabetic should not attempt fasting.
• If you fast, stay hydrated as you’re not getting any liquids from food. Most regimens include fluids in ample amounts, so load up prior to and during your fasting.
• It’s a change to your eating pattern which can lead to mental stress and impact sleep rhythms.
• The risk of overlooking and maintaining balanced and healthy meals and the impulse to binge due to longer periods of hunger.
• Some nutritionists still aren’t sold on the weight loss and say it’s temporary. While short-term results were promising, there are no long-term studies that we could find that showing extended weight loss results.

Carb Cycling

Where Intermittent Fasting limits food for specific days, Carb Cycling curtails your carbohydrates in a similar strategy. Based on individual preference, you restrict carb intake to low, medium, and high amounts in a 7-day cycle, or a low-week, high-week course dependent on your needs. This can be planned for in daily, weekly or monthly if your goal is centered around losing weight or incorporating the cycling into a fitness program.

(We found a great reference in Healthline.com that has a sample week for guidance.)

The key to remember: you still should only eat good carbs. Those high in fiber, slow to digest and most important, unprocessed. Look to our Carbs and Sugar blog, but as a recap these include whole grains, sweet potatoes, fruit, beans and vegetables. (Source)

The Advantages of Carb Cycling:

(IIFYM Source)

We know that many diets eliminate or drastically limit carbs and may not work for certain people as the exclusion of carbs often gets to be too much and results in people giving up. With Carb Cycling, it makes it easier to lose weight because you don’t have to restrict yourself to such a large extent. Even on low carb days, you’ll be able to eat carbs the next day (or in the next two) so it doesn’t seem like you’re depriving yourself too much.

On low carb days, you’re minimizing fat gain and increasing insulin sensitivity, maintaining better body composition.  On high carb days, your body burns more calories and increases the hormone leptin, which keeps you from feeling hungry. High carb days also make you energized and replenish glycogen stores that fuel your muscles.

The Disadvantage of Carb Cycling:

(IIFYM Source)

Despite the articles and publications accessible online, there is no long-term, medical research that suggests the program influences weight loss or calories burned.  As with most dieting, overall caloric intake will be the most significant factor is obvious results. For someone who strictly cares about weight loss with no focus on performance, the Carb Cycling may be unnecessary and complicate a simple process that doesn’t need to be difficult.

In the end, everything comes down to what you can adherence to. Whether Intermittent Fasting or Carb Cycling will be effective depends on your personal preferences and if you can stay consistent with it.

We can’t say it enough: consult with your physician before embarking on any substantial diet changes! If you do want more information from published materials, please feel free to check out our Amazon recommendations through our affiliate links. Thanks for your support!