Intermittent fasting (IF) is touted as a simple, effective way to manage blood sugar, reverse prediabetes, and lose weight. However, IF is not for everyone, and it can have potential drawbacks and challenges that can worsen future health outcomes for some. Here are some of the most common limitations I see in my clients who have tried IF.
Firstly, fasting may lead to hunger pangs and food cravings, which can be difficult for some to manage. The most common fasting window is 16 hours, and jumping into this after a typical overnight fasting window of 8-10 can be difficult, to say the least! Fighting ongoing hunger and cravings is ultimately unsustainable. While devotees of IF will tell you to just tough it out, the reality is that for some people fasting much of the day leads to compensatory eating at night, and these late night calories are not usually coming from broccoli and chicken.
Many people are not metabolically healthy enough to get through IF without negative consequence. If there is underlying blood sugar issues like reactive hypoglycemia (which is unlikely to show up on a standard blood test) or blood sugar instability, they may suffer from headaches, fatigue, vertigo and irritability when fasting.
Underlying endocrine or hormone imbalances (commonly labeled as adrenal fatigue or cortisol dysregulation) are also negatively impacted by longer fasting periods, as the body perceives the lack of food as a stressor, driving up stress hormones as blood sugars fall.
Both of these issues can increase the risk of overeating during non-fasting periods, leading to weight gain over time. Research shows a slight advantage to having an earlier eating window (such as having breakfast and lunch) and beginning one’s fast earlier in the evening, but that tends to be the most difficult to accomplish with family and social obligations. So the reality looks like fasting all day and then making indiscriminate and less healthy choices at dinner which can exacerbate weight issues, disordered eating habits, and nutrient deficiencies.
IF also increases the risk of muscle loss, a HUGE no-no for anyone over 45 and for women especially, who have to fight harder to build and keep the muscle we have. In my opinion, no method of health promotion that sacrifices muscle is a worthwhile endeavor. If one wants to try intermittent fasting, it is critical to ensure sufficient protein and nutrients are consumed in the eating window. This is enough of a challenge among unrestricted eaters, so I’m dubious about long term benefit when anyone is looking to extend their fast beyond 14 hours, as it’s a challenge to get enough nutrients in less than 10 hours a day.
While there is promising research on IF reducing insulin and blood sugar levels, this is only one tool to accomplish this. There are many tools available, so before you jump on the IF bandwagon, you may want to critically analyze whether or not this is ideal in your situation, for your body, with your personal and medical history.
Furthermore, individuals with medical conditions such as diabetes may require medical supervision before attempting IF, especially if medications are part of one’s treatment plan.
Have you tried intermittent fasting? If so, I’d love to hear your experience below! Did you love it or hate it?