New Years resolution season is bearing down upon us again. Which means, for most people (the majority in annual polls, who list ‘lose weight,’ ‘get in shape,’ or something similar as their top resolution), January will kick off with new exercise routines, new diets, and new lifestyles.

But, for almost all of those people, by the time they hit February, they’ll have given up completely, and returned to exactly what they were doing the year before.

As research on habits makes clear, one of the keys to success amongst the people who actually do manage to sustain change is starting small. Make the minimum shift needed to see results, and then build slowly from there over time. Whereas most resolutioners attempt the opposite, jumping straight to drastic change – go keto! run five miles every morning before work! – and it’s that extreme approach that so quickly derails them.

I was therefore surprised to see I’ve only mentioned in passing what I’ve generally found to be the easiest and most impactful simple first step for people looking to lose weight: intermittent fasting (or “IF,” as it’s often called).

Happily, IF isn’t just an effective way to shed excess fat; research is increasingly showing it’s likely a way to increase your lifespan, and to stave off all kinds of serious illness (whether cancer, heart disease, or diabetes), too. If you want to dive deeper, there are a ton of great resources out there: reader-friendly articles on the how and why, scientific review papers exploring the underlying journal research, even a (free!) app for timing the daily fasting window.

But, really, the core of IF is simple enough that you can jump in based on just two bullet points.

• For 16 hours a day, don’t consume any calories. (Water, tea, and coffee are fine.)
• For 8 hours a day, eat per usual.

And that’s it.

I do this myself, eating all of my calories between roughly 1pm and 9pm. I skip breakfast (drinking a bunch of coffee instead), have lunch at 1:00pm, eat some snacks through the afternoon at work, and then have dinner at home with Jess, before stopping eating for the night at about 9:00pm. (Depending on your own work and life schedules, feel free to shift that as needed. A bunch of my clients and friends do 12pm to 8pm, or 2pm to 10pm, though really any window works.)

Crazy enough, for almost everyone I’ve worked with, this change alone is sufficient to kick off slow and steady and sustainable leaning out. And though it sounds like it would be unpleasant, after a couple of days of adjusting to the new circadian food rhythm, people are usually so not hungry during the fasts that they’ll sometimes forget to start eating for an hour or two after the fasting window ends.

As I said, the whole thing really boils down to just that 16/8 formula. But, based on frequent questions / things I’ve seen doing and coaching this, I do have a handful of small, hopefully useful additional pointers:

• If you normally put milk (or even better – given the lesser impact on insulin levels – cream) into your coffee, feel free to keep doing so during the fast. It doesn’t seem to make much difference.
  
• If you work out during the fasting window (as I do), you’re similarly probably just fine as is. Though, if you’re trying to add muscle, and are worried missing the post-workout feeding window will undercut your ‘gainz,’ chug down 15g of essential amino acids as a pre-workout.
  
• If you’re a lady, you might consider trying a 14-hour fast and a 10-hour eating window instead. Some women seem to have hormonal side effects (irregular periods, bone density decreases) when doing 16/8 over the long-term. A 14/10 approach appears to provide the vast majority of the same benefits, but without triggering female-specific side effects.
  
• And, finally, while the first step is indeed to just change food timing, without shifting or limiting what you eat during the eight-hour window (as that’s enough to kick off fat loss and biomarker improvements by itself), achieving optimal health and fitness probably involves making other (fortunately similarly incremental) changes over time. Still, as I said before, starting with a manageable beachhead like IF’ing, and quickly seeing results, tends to lead much more effectively to long-term success – and further positive changes over time – than just trying to do everything all at once, and then dropping it all after two or three weeks.

So, in short, if you have physique (or general health) resolutions in mind this year, consider giving Intermittent Fasting a whirl. Hell, you can even hop in today, and roll into the New Year with two weeks of practice – which, in turn, should substantially up the odds that you’ll keep sticking with it, and keep seeing real results, over the year ahead.