Interested in intermittent fasting (IF) for fat loss without throwing your SHMEC out of check? Here’s a simple way to integrate this eating pattern that cycles between periods of fasting and eating.

When it comes to fat loss IF can be an incredibly effective and sustainable approach. However, many people find it difficult to fast. Luckily, not all IF approaches are the same. So, how can we make IF a more realistic, sustainable, and effective approach for fat loss?

A growing body of research suggests that the timing of the fast is key. Like most biological processes, our metabolisms have evolved to be in sync with the day/night cycle known as the circadian rhythm. Essentially, fasting is embedded within our physiology. Intermittent fasting where all meals fit into an early daytime eating window (7 am to 3 pm) compared to spread out over 12 hours (between 7 am and 7 pm), may improve metabolic health and help us to burn more calories.

At Metabolic Living, we encourage everyone to use an eating approach that works for them and is sustainable to them. If you struggle with IF because you find it too restrictive, or you simply need food in the evening to help with sleep, here’s how (and why) to increase and/or shift your fasting window slowly.

Ghrelin, a hormone peptide released from our gastrointestinal tract, is related to when we get hungry. Its main role is to increase the desire to eat. It works by stimulating neurons in the brain that drive the desire to eat. In other words, it is a food anticipatory signal and it effectively gets us to eat at a particular time of day. Do you notice that you’re usually hungry at the same time each day? That’s probably Ghrelin! So, if you are someone who normally eats your meals at the same times each day (plus or minus 20 minutes), your Ghrelin secretion will start to match when you typically eat. It also gets incoming signals from low levels of blood sugars. Not eating “on the clock” for those of us who need to eat every 2-3 hours can be very disruptive because not eating activates these neurons in the brain that make us want to eat. Hello, “hangry”.

In summary: regularity of eating = regularity of ghrelin secretion = hunger at regular intervals.

Gut-Brain Connection & Shifting Neural Circuits

Due to neural circuits that link the Ghrelin system (in the gut) to neural circuits that control hunger (in the brain) shifting periods of fasting and eating is a form of neural plasticity.

“Neural plasticity” refers to the capacity of the nervous system to modify itself, functionally and structurally, in response to experience…” (1)

And because it’s a form of neural plasticity, an approach that allows the nervous system to adapt may decrease the occurrence or intensity of metabolic compensation (SHMEC going out of check).

Shifting periods of eating and fasting can be challenging, but it’s not impossible – if we do it slowly using SHMEC to guide us!

Start by shifting the time of your first or last meal by 45 minutes per day or every few days. Of course, this can vary, but the research supports this approach for shifting neural circuits.

For example, let’s say you eat your first meal at 7 am every day and your last meal by 8 pm each day (plus or minute 20-30 minutes). Using this approach, you may eat your first meal 45 minutes later or, you may eat your last meal 45 minutes sooner. Which one keeps SHMEC in check the most?

Consider a phased approach to intermittent fasting

If you want to develop flexibility over when you eat and/or shift your eating/fasting windows to align with your circadian rhythm, adjust by 45-minute increments at a time. Check-in with SHMEC and continue to adjust your IF approach until you find what works best for you and your metabolism.

References

  1. von Bernhardi R, Bernhardi LE, Eugenín J. What Is Neural Plasticity? Adv Exp Med Biol. 2017;1015:1-15. doi: 10.1007/978-3-319-62817-2_1. PMID: 29080018.

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