Intermittent Fasting: Does It Truly Live Up to Its Hype?

Intermittent fasting. Can it help you lose more weight without counting calories? Improve blood glucose levels? Or live longer? Get answers here.

Intermittent Fasting: Does It Truly Live Up to Its Hype?

Intermittent fasting.

Can it help you lose more weight than a traditional, energy-restricted diet — without the hassle of calorie-counting? Improve insulin sensitivity for more stable blood sugar levels? Live longer?

Let’s find out together. In this article, we’ll cover everything you need to know about intermittent fasting, including:

  • What it is
  • Its (research-backed) health benefits, and
  • A bunch of useful tips on how to incorporate it into your life for best results

What is intermittent fasting?

Unlike other diets, intermittent fasting doesn’t care about what you eat, but when you eat.

With intermittent fasting, you switch between fasting (i.e., not eating) and eating regularly.

The 3 most widely practiced intermittent fasting types practiced today are:

1️⃣ 16:8 diet: Fast for 16 hours, leaving an eating window of 8 hours. E.g., you finish your last meal of the day by 8 pm, and only eat again on noon the next day.

2️⃣ 5:2 diet: Eat as usual 5 days a week, then reduce your calorie consumption to 500-600 calories on the remaining days. Note that the fasting days shouldn’t be done back-to-back. E.g., you fast on Saturdays and Sundays (❌); you fast on Mondays and Thursdays (✅).

3️⃣ Alternate day fasting: Pretty much as it sounds. You fast every other day. For some people, alternate day fasting means avoiding solid foods on fasting days, while others allow up to 500 calories.

Now, because you must be wondering — the type of intermittent fasting you choose comes down to 2 primary things: 1) your lifestyle and 2) your physique goals.

#1 (lifestyle) is kind of self-explanatory.

E.g., alternate day fasting wouldn’t make sense for you if you’re extremely physically active across all days of the week (you might run out of steam on fasting days!)

And as for #2 (physique goals)? We’ll cover that in more detail in a bit.

Does intermittent fasting work for weight loss?

OK. So, how does intermittent fasting fare on the weight loss front?

Well, there are only 2 main things you need to know:

  1. Intermittent fasting works for weight loss. When initiated, intermittent fasting tends to cause more weight loss than no intervention. Researchers still aren't sure why intermittent fasting is associated with better hunger and appetite regulation — individuals tend to either passively consume fewer calories or better tolerate consuming fewer calories.
  2. But it’s not any better than traditional calorie-restricted diets. Here’s the catch. 🎣 Intermittent fasting doesn’t typically cause more weight loss than a “traditional” diet with continuous calorie restriction.

Intermittent fasting health benefits

But either way, that still means intermittent fasting works for weight loss, right? Plus, doesn't it offer several impressive metabolic health benefits — from lowered blood pressure to triglycerides to HbA1c*?

*HbA1c is your average blood glucose level for the last 2 to 3 months.

Welll. The truth is that human studies on the health benefits of intermittent fasting have been mixed and limited.

We must also entertain the possibility that the benefits we see resulted simply from weight loss. After all, the body of evidence linking weight reduction and favorable metabolic changes, including:

✨ Improved insulin sensitivity

✨ Lowered inflammatory markers

✨ Reduced triglycerides and systolic blood pressure

… is way more extensive and credible than those linking intermittent fasting and its various "health benefits".

Of course, this isn’t to say intermittent fasting doesn’t improve metabolic health.

Instead, the point we’re driving at is that, until more research is done, we cannot reasonably conclude that intermittent fasting provides additional health benefits beyond what’s typically seen from weight reduction.

What to know before trying intermittent fasting

Whatever. 🤷 As long as intermittent fasting works for weight loss, I’m in.” — is this you?

If so, there are 2 things you need to know before jumping on the intermittent fasting bandwagon:

1️⃣
There appears to be great inter-individuality in hunger and appetite regulation. While the overall trend is that intermittent fasting results in lower hunger and higher fullness, research suggests that not all individuals experience improved appetite control. I.e., intermittent fasting might not work for you.

On the other hand … here are 5 appetite regulation strategies that might just work for you:

How to Stop Appetite Naturally (5 Hunger Management Methods)
Hunger can quickly derail your weight loss aspirations. But you don’t have to be hungry — here’s how to stop appetite naturally while on a diet.
2️⃣
Intermittent fasting is not your best choice if you’d like to maximize muscle gain in a calorie deficit. What do you need for optimal muscle growth while in a calorie deficit? Enough protein. Do you think you could hit your required protein intake with the 5:2 or alternate day fasting methods? Mm hmm. It’ll be challenging, which brings us to …

How to approach intermittent fasting

If you’re serious about trying intermittent fasting and building as much muscle mass as possible, the best way forward is to adopt the 16:8 intermittent fasting type, while ensuring:

Also, an important reminder: always seek clearance from your primary healthcare doctor before you start intermittent fasting.

Don’t forget the other core principles

Just because intermittent fasting is primarily concerned about when you eat doesn’t mean you can treat your stomach like a trash can. 🗑️

You should still stick to basic, good nutritional practices, such as:

Beyond all that, don’t forget to strength train — because that provides the stimulus your muscles need to grow.

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References

Elsworth, Rebecca L., et al. “The Effect of Intermittent Fasting on Appetite: A Systematic Review and Meta-Analysis.” Nutrients, vol. 15, no. 11, June 2023, p. 2604. PubMed, https://doi.org/10.3390/nu15112604.

Farhana, Aisha, and Anis Rehman. “Metabolic Consequences of Weight Reduction.” StatPearls, StatPearls Publishing, 2023. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK572145/.

Hoddy, Kristin K., et al. “Changes in Hunger and Fullness in Relation to Gut Peptides before and after 8 Weeks of Alternate Day Fasting.” Clinical Nutrition (Edinburgh, Scotland), vol. 35, no. 6, Dec. 2016, pp. 1380–85. PubMed, https://doi.org/10.1016/j.clnu.2016.03.011.

Keenan, Stephen J., et al. “Intermittent Fasting and Continuous Energy Restriction Result in Similar Changes in Body Composition and Muscle Strength When Combined with a 12 Week Resistance Training Program.” European Journal of Nutrition, vol. 61, no. 4, June 2022, pp. 2183–99. Springer Link, https://doi.org/10.1007/s00394-022-02804-3.

Liu, Deying, et al. “Calorie Restriction with or without Time-Restricted Eating in Weight Loss.” New England Journal of Medicine, vol. 386, no. 16, Apr. 2022, pp. 1495–504. Taylor and Francis+NEJM, https://doi.org/10.1056/NEJMoa2114833.

Mamerow, Madonna M., et al. “Dietary Protein Distribution Positively Influences 24-h Muscle Protein Synthesis in Healthy Adults123.” The Journal of Nutrition, vol. 144, no. 6, June 2014, pp. 876–80. PubMed Central, https://doi.org/10.3945/jn.113.185280.

Mandal, Sumona, et al. “Intermittent Fasting: Eating by the Clock for Health and Exercise Performance.” BMJ Open Sport & Exercise Medicine, vol. 8, no. 1, Jan. 2022, p. e001206. bmjopensem.bmj.com, https://doi.org/10.1136/bmjsem-2021-001206.

Parr, Evelyn B., et al. “Eight-Hour Time-Restricted Eating Does Not Lower Daily Myofibrillar Protein Synthesis Rates: A Randomized Control Trial.” Obesity (Silver Spring, Md.), vol. 31 Suppl 1, no. Suppl 1, Feb. 2023, pp. 116–26. PubMed, https://doi.org/10.1002/oby.23637.

Patterson, Ruth E., et al. “INTERMITTENT FASTING AND HUMAN METABOLIC HEALTH.” Journal of the Academy of Nutrition and Dietetics, vol. 115, no. 8, Aug. 2015, pp. 1203–12. PubMed Central, https://doi.org/10.1016/j.jand.2015.02.018.

Ryan, Donna H., and Sarah Ryan Yockey. “Weight Loss and Improvement in Comorbidity: Differences at 5%, 10%, 15%, and Over.” Current Obesity Reports, vol. 6, no. 2, June 2017, pp. 187–94. PubMed Central, https://doi.org/10.1007/s13679-017-0262-y.

Stokes, Tanner, et al. “Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training.” Nutrients, vol. 10, no. 2, Feb. 2018, p. 180. PubMed Central, https://doi.org/10.3390/nu10020180.

Welton, Stephanie, et al. “Intermittent Fasting and Weight Loss: Systematic Review.” Canadian Family Physician Medecin De Famille Canadien, vol. 66, no. 2, Feb. 2020, pp. 117–25.