To be frank, "you're not doing it right." Although the levels of any diet can vary, IF can work for anyone when properly applied. However, you should keep in mind that IF does not come in a one size fits all package. There are a variations and levels of IF. The key is the "intermittent" part. The minimum is 16/8, but you can go much longer and with varying degrees of frequency. You have to experiment and choose the protocol that works best for you and fits your lifestyle.


From the little that you've given us (low energy), I suspect that your limitation may have to do with your diet. Is it the Warrior diet? Vegan? The Ketogenic diet? The PSMF? Remember, that an exercise routine centered around anaerobic training will require a different form of nutritional intake than one focused on aerobic training. If you haven't yet determined your best diet, you have to experiment with food, timing and calories to determine which has the most significant positive impact for your needs.


Since we all have different goals, IF needs to be personalized, and just like an exercise routine -- and diet -- that takes practice. On the other hand, you may just as likely not given it enough time. It took me nearly 2 weeks before I could get over the weakness and shaking that comes from fasted anaerobic training.


The last, but not least aspect of IF is rest. Are you getting enough of it, and is it meaningful continuous rest? Nothing can sap your energy faster than lack of sleep. There are countless diets to suit different people to help them reach their health and fitness goal. But remember, the IF just puts you in a more productive environment, its still the foods you consume that has the biggest impact on your success, to how you look and feel.