Intermittent fasting for beginners can feel overwhelming when every fitness influencer has a different opinion about it. Some swear by 16:8, others push 20:4, and a few insist you need to fast for 72 hours to see results. I think most of that is noise.
Here's the thing: intermittent fasting is just a schedule. You eat during certain hours and don't eat during others. That's it. There's no magic food list, no special supplements, and no secret protocol that makes it work better than the basics. The reason it helps people lose weight is simple: when you have fewer hours to eat, you tend to eat less.
I've spent years working on BodyBuddy, helping real people build sustainable habits around food. And intermittent fasting comes up constantly. So I wanted to write the guide I wish existed when I first looked into it: straightforward, no hype, and honest about both the benefits and the downsides.
What intermittent fasting actually is (and isn't)
Intermittent fasting (IF) is a pattern of eating that cycles between periods of eating and not eating. It says nothing about which foods to eat. It only tells you when to eat them.
This matters because a lot of people treat IF like a diet. They combine it with keto, or paleo, or carnivore, and then credit fasting when the weight comes off. But the fasting itself is just one variable. You can fast perfectly and still gain weight if you eat 4,000 calories in your eating window.
IF is not a miracle. It is a tool. A useful one for many people, but not the only one.
The most common intermittent fasting schedules
There are a few popular approaches. I'd recommend starting with the easiest one and only adjusting if you have a specific reason to.
16:8 (the one most people should start with)
You eat within an 8-hour window and fast for 16 hours. For most people this means skipping breakfast and eating from noon to 8 PM. The 16-hour fast includes sleep, so it's less dramatic than it sounds.
This is the schedule I recommend for beginners because it barely changes your life. If you already don't eat much before lunch, you might be doing it accidentally.
14:10
A gentler version. You eat within a 10-hour window. Good if 16:8 feels too restrictive at first, or if you work out in the morning and need fuel.
5:2
You eat normally five days a week and eat around 500-600 calories on two non-consecutive days. This works for people who hate daily restrictions but can handle two tough days.
20:4 and OMAD (one meal a day)
These are more aggressive. I don't recommend them for beginners. The hunger gets intense, it's hard to get enough nutrients in such a small window, and the dropout rate is high. If 16:8 works for you after a few months, then maybe experiment. But there's no evidence that longer fasts produce meaningfully better results for weight loss.
What the research actually says
A 2022 meta-analysis in the Annual Review of Nutrition looked at 27 trials and found that intermittent fasting produced similar weight loss to traditional calorie restriction. Not more, not less. The advantage was adherence: some people find it easier to follow a time rule than count every calorie.
A 2023 study from the University of Illinois tracked 90 adults on 16:8 fasting for 12 weeks. Average weight loss was about 3% of body weight. Nothing dramatic, but meaningful. The participants who combined IF with light exercise lost closer to 5%.
There are also studies showing benefits for insulin sensitivity, inflammation markers, and metabolic health. But most of these used small samples or short timeframes. The honest summary: IF probably has some metabolic benefits beyond just eating less, but calorie reduction is still doing most of the heavy lifting.
How to start intermittent fasting this week
Don't overthink it. Here's what I'd do:
- Pick 16:8 as your starting schedule. Eat from noon to 8 PM (or adjust the window to fit your life).
- For the first week, just focus on the timing. Don't change what you eat yet. Let your body adjust to the new schedule.
- Drink water, black coffee, or plain tea during your fasting window. These won't break your fast.
- If you feel shaky or lightheaded, eat. Fasting should feel mildly uncomfortable at times, not dangerous.
- After the first week, start paying attention to what you eat during your window. Protein and fiber will keep you full longer.
Most people find the first 3-5 days are the hardest. Your body is used to eating at certain times, and those hunger signals are real. They fade. By week two, most people report that they don't even think about food until their eating window opens.
Common mistakes that trip up beginners
I've seen these patterns repeat over and over with people who try IF and quit within a month.
Eating too much during the window
The eating window is not an invitation to binge. If you fast for 16 hours and then eat a whole pizza, a pint of ice cream, and a bag of chips, you will not lose weight. You'll probably gain it. IF reduces your eating time, but you still need to eat reasonable portions.
Starting too aggressive
Going straight to 20:4 or OMAD when you've never fasted before is a recipe for failure. Start easy. Build the habit. You can always tighten the window later.
Ignoring protein
When you have fewer hours to eat, every meal matters more. Getting 25-40 grams of protein per meal helps you stay full and preserves muscle mass. If you're fasting and eating mostly carbs and snacks during your window, you'll be hungry all day and lose muscle along with fat.
Being too rigid about the clock
If you normally eat noon to 8 PM but a friend invites you to breakfast at 9 AM on Saturday, go eat breakfast. One day off schedule won't undo anything. The people who succeed with IF long-term are flexible about it. It's a default, not a prison sentence.
How BodyBuddy helps with intermittent fasting
One of the biggest challenges with IF is the space between meals. You're not eating, but you're thinking about eating. That's where having a coach in your pocket makes a real difference.
BodyBuddy sends you check-ins throughout the day over text message. During your fasting window, it can remind you why you're doing this, suggest ways to stay busy, or just be someone to talk to when the cravings hit. During your eating window, it helps you make good choices about what to eat and how much.
It's not a calorie tracker or a macro counter. It's more like having a friend who actually knows about nutrition and holds you accountable without being annoying about it. A lot of our users combine IF with daily BodyBuddy check-ins and say the combination is what finally made fasting stick.
Who should not try intermittent fasting
IF is not for everyone, and I think the fasting community downplays this too much.
- If you have a history of eating disorders (anorexia, bulimia, binge eating), fasting can trigger harmful patterns. Talk to a doctor or therapist first.
- If you're pregnant or breastfeeding, you need consistent nutrition. Now is not the time to experiment with meal timing.
- If you take medications that require food at specific times (like certain diabetes medications), fasting may interfere with your treatment.
- If you're under 18, your body is still growing. Regular meals matter.
There's no shame in deciding IF isn't for you. Plenty of people lose weight and get healthy without ever fasting.
Frequently asked questions
Does intermittent fasting slow down your metabolism?
Short-term fasting (16-24 hours) does not meaningfully slow metabolism. Extended fasts of several days can, but that's not what we're talking about here. A 2014 study in Translational Research found that fasts under 48 hours actually showed a slight metabolic increase. Your metabolism is more resilient than most people think.
Can you work out while fasting?
Yes. Most people can do moderate exercise during a fast without problems. Some people prefer it, saying they feel lighter and more focused. For heavy lifting or intense cardio, you might want to schedule workouts near the start of your eating window so you can refuel afterward. Listen to your body.
What breaks a fast?
Anything with calories technically breaks a fast. Water, black coffee, and plain tea are fine. Adding cream, sugar, or sweetener to your coffee is debatable, but if we're being strict, yes, those break a fast. Most people won't notice a difference from a splash of cream, but if you want to be precise, keep it to zero calories.
How long before you see results?
Most people notice reduced bloating and better energy within the first week. Actual weight loss typically shows up after 2-3 weeks of consistent fasting combined with reasonable eating. Expect to lose about 0.5-1 pound per week, which is the same rate as any sustainable weight loss approach.
Is intermittent fasting better than counting calories?
Neither is objectively better. They're different tools. Some people find it easier to watch the clock than count every gram of food. Others prefer the precision of calorie tracking. The best approach is the one you'll actually stick with for months, not just weeks.
The bottom line
Intermittent fasting for beginners doesn't need to be complicated. Pick 16:8, try it for two weeks, and see how you feel. Pay attention to what you eat during your window, get enough protein, and don't punish yourself for imperfect days.
If it works for you, great. If it doesn't, that's fine too. Weight loss and health are long games, and the approach that fits your life will always beat the theoretically optimal approach that you can't maintain.
Want some daily support while you figure it out? BodyBuddy coaches you through it over text, one meal at a time. No apps to open, no food to log. Just real conversations about real food choices.