Paleo Intermittent Fasting: 16:8 Plan and Evidence

By Paleo Life Coach Editorial Team · Last updated September 26, 2026 · Trials from PubMed; nutrition from USDA FoodData Central

Paleo tells you what to eat. Intermittent fasting tells you when. They answer different questions, which is why so many people try paleo and intermittent fasting together: whole foods, inside a shorter eating window. The pairing is easy to set up and easy to get wrong, mostly by squeezing too little food, especially protein, into too few meals. Below you’ll find a step-by-step way to combine them, a 16:8 paleo day counted with USDA data, and a plain summary of what the fasting trials found, which is more modest than the internet suggests.

The quick version: You can combine paleo with intermittent fasting by eating paleo foods inside a daily window, most often 8 hours (16:8). Trials show time-restricted eating works about as well as ordinary calorie cutting, not better. Start paleo first, then shorten your window gradually, and plan meals so you still reach your protein target.

What is intermittent fasting, and how is it different from paleo?

Intermittent fasting (IF) is a meal-timing pattern, not a food list. The common versions are:

Time-restricted eating: eat within a set window each day. NIH’s MedlinePlus Magazine describes windows from 12 hours (for example 7 a.m. to 7 p.m.) down to 8 hours.
5:2: eat normally five days a week and eat very little on two non-consecutive days.
Alternate-day fasting: alternate normal days with very-low-calorie days.

Paleo is the opposite kind of rule. It sets which foods count (meat, fish, eggs, vegetables, fruit, nuts, seeds and healthy fats) and drops grains, legumes, dairy, refined sugar and processed food, as Harvard’s paleo diet review summarizes. It says nothing about timing. Put them together and you get a diet with a food rule and a clock rule.

Does combining paleo and intermittent fasting work better?

No trial has tested the combination directly. The evidence is on each separately, plus one study that followed people choosing between them.

Does combining paleo and intermittent fasting work better?
Study	Who and what	Result
Lowe et al., JAMA Intern Med 2020 (TREAT)	116 adults with overweight or obesity; 16:8 eating (noon-8 p.m.) vs three structured meals, 12 weeks	16:8 group lost 0.94 kg, meal group 0.68 kg; difference between groups not significant. Authors: time-restricted eating alone “is not more effective in weight loss than eating throughout the day”
Liu et al., NEJM 2022	139 adults with obesity; calorie restriction with an 8 a.m.-4 p.m. window vs calorie restriction alone, 12 months	8.0 kg vs 6.3 kg lost; difference not significant. No meaningful difference in body fat or metabolic risk factors
Jospe et al., Am J Clin Nutr 2020	250 adults who chose IF, paleo or Mediterranean eating with brief advice, 12 months	Weight change: IF -4.0 kg, Mediterranean -2.8 kg, paleo -1.8 kg. Still following their diet at 12 months: 54% IF, 57% Mediterranean, 35% paleo. Between-group differences mostly not significant

What the trials say, in plain terms:

The window isn’t magic. When calories are matched, as in the Liu trial, eating in a window didn’t add meaningful weight loss.
IF helps if it helps you eat less. For some people a shorter window is simply an easier way to cut calories.
Sticking with it is the hard part. In the Jospe study, only about a third of people who chose paleo were still following it a year later, and the authors note the comparison wasn’t randomized. That’s a reason to choose a version of paleo and fasting you can keep, rather than the strictest one.

For a realistic look at early results on paleo, see paleo weight loss in 30 days.

Which fasting window should you choose?

Pick the shortest window you can keep without feeling awful or under-eating. For most people starting out, that’s 12 or 14 hours of fasting, not 16.

Which fasting window should you choose?
Schedule	Example eating hours	Meals that fit	Best for
12:12	7 a.m. – 7 p.m.	Three meals, no late snacking	Beginners; mostly means “stop eating after dinner”
14:10	9 a.m. – 7 p.m.	Three meals or two meals and a snack	People who don’t mind a later breakfast
16:8	Noon – 8 p.m.	Two meals and a snack	People who aren’t hungry in the morning
Early 8-hour window	8 a.m. – 4 p.m.	Breakfast, lunch, early dinner	Early risers; the Liu trial used this window
5:2	Normal eating 5 days, 2 very-low days	Normal paleo meals most days	People who prefer a couple of hard days to a daily clock

Windows from the MedlinePlus description and the TREAT and Liu trial protocols; “best for” is practical guidance, not trial evidence.

How to combine paleo and intermittent fasting, step by step

Start with paleo alone for two to four weeks. Changing what you eat and when you eat at the same time makes it hard to tell which change is causing headaches, low energy or hunger. The first weeks of paleo can bring the tiredness described in our paleo flu guide.
Set your protein target before your window. Harvard’s protein page gives the RDA as 0.8 g per kilogram of body weight, “just over 7 grams for every 20 pounds,” about 50 g for a 140-pound person and 70 g for a 200-pound person. Many active people aim higher; our paleo diet protein guide walks through the ranges.
Close the kitchen after dinner. Stop eating two to three hours before bed. That alone gives most people a 12-hour fast.
Push breakfast later by an hour a week. Move from 12:12 toward 14:10, and only go to 16:8 if you’re comfortable there.
Build each meal around protein. With two or three meals instead of four or five, each one has to carry more. Aim for 25-40 g of protein per meal.
Drink water, and keep coffee or tea plain during the fast. Cream, collagen or butter in coffee adds calories and ends the fast for most definitions. Our is coffee paleo article has the numbers on add-ins.
Reassess after four weeks. If you’re more tired, sleeping badly, bingeing at the first meal or losing strength, widen the window.

What does a 16:8 paleo day look like?

Here’s a noon-to-8 p.m. day with two meals and a snack, counted from USDA data. It’s built for a 180-pound adult whose protein RDA is about 65 g (82 kg × 0.8).

What does a 16:8 paleo day look like?
Meal	Foods	Calories	Protein (g)	Carbs (g)	Fiber (g)
Noon: first meal	3 eggs cooked in 1 tsp olive oil, ½ cup cooked spinach, ½ avocado, 1 cup strawberries	437	23.8	22.1	9.8
3:30 p.m.: snack	1 oz almonds, 1 medium apple	259	6.5	31.2	7.9
7 p.m.: dinner	5 oz baked salmon, 150 g baked sweet potato, 1 cup broccoli, 1 tbsp olive oil	601	38.1	42.3	10.1
Day total		1,297	68.4	95.6	27.8

Source: USDA FoodData Central SR Legacy: raw whole egg, boiled spinach, California avocado, strawberries, almonds, apple with skin, farmed Atlantic salmon (cooked, dry heat), baked sweet potato, boiled broccoli, olive oil. Our arithmetic from USDA per-100 g values.

What the numbers show:

Protein fits, barely. 68 g clears the 65 g RDA for this person, but only because dinner carries 38 g. Skip the salmon and the day falls well short.
Calories are modest. About 1,300 calories is a weight-loss day for most adults. If you’re not trying to lose weight, or you train hard, add a larger first meal or a second protein at the snack. Use the TDEE and macro calculator to find your own number.
Fiber is solid. About 28 g comes from vegetables, fruit and nuts, no grains needed.

For a full week of paleo meals you can compress into a window, start from the 7-day paleo meal plan and merge breakfast into lunch.

Mistakes people make with paleo intermittent fasting

Under-eating protein. The most common problem with two meals a day. Plan protein first.
Breaking the fast with a huge fruit-and-nut snack. Paleo-legal, but it’s easy to eat 600 calories of dates and cashews in ten minutes.
Starting both at once. You won’t know what’s working or what’s making you feel rough.
Treating the window as permission. A 16:8 window full of paleo desserts won’t do what a 16:8 window of real meals does.
Training hard while fasted without adjusting. If performance drops, move your window so you eat before or soon after training. See paleo for athletes.

Who should not try intermittent fasting?

Fasting isn’t for everyone. NIH’s MedlinePlus Magazine states that it “is not safe for everyone, especially those with health conditions like diabetes, kidney disease, or heart-related issues.” A 2023 review on intermittent fasting and disordered eating says people with an eating disorder or a history of one “should never be encouraged” to fast, and that children, older adults and pregnant or breastfeeding women should not take part because safety hasn’t been studied in those groups.

Talk to your doctor before trying intermittent fasting if you take insulin or other glucose-lowering medication, take blood pressure medication, have kidney or heart disease, are underweight, or have ever had an eating disorder.

Frequently asked questions about paleo and intermittent fasting

Can you do paleo and intermittent fasting together?

Yes. Paleo sets which foods you eat and intermittent fasting sets when you eat, so they don’t conflict. Most people eat paleo meals inside a 10- or 8-hour window. Start paleo first for a few weeks, then shorten your eating window gradually, and plan each meal so you still reach your daily protein.

Is intermittent fasting better than paleo for weight loss?

Neither has proven clearly better. In the Jospe 2020 study, people who chose intermittent fasting lost 4.0 kg over a year versus 1.8 kg for those choosing paleo, but people picked their own diet, and differences between groups were mostly not significant. What predicted results most was whether people kept following their plan.

Why is 16 hours the magic number for fasting?

It isn’t magic. The 16:8 schedule is popular because it’s easy to explain and it fits a skip-breakfast routine. In the TREAT trial, 16:8 eating with no other changes produced no more weight loss than three regular meals over 12 weeks. A 12- or 14-hour fast is a reasonable place to start.

What is the healthiest form of intermittent fasting?

No form has been shown to be healthiest overall. In the Liu 2022 trial, an early 8 a.m. to 4 p.m. window combined with calorie limits worked about as well as calorie limits alone over a year. The healthiest version is the one that lets you eat enough protein, fiber and total food without bingeing, and that you can keep up.

How much weight can you lose with paleo and intermittent fasting?

It depends mostly on your calorie deficit. In a year-long trial, calorie restriction with an eating window produced about 8 kg of weight loss versus 6.3 kg with calorie restriction alone, a difference that wasn’t significant. Expect results similar to any well-followed calorie-reduced plan, and be wary of promises of rapid loss.

Your next step: fix the food, then the clock

Get two to four weeks of steady paleo eating under your belt, then close the kitchen after dinner and see how a 12- or 14-hour fast feels. Plan protein first, and widen the window if energy or sleep suffer. For ready-made meals to drop into your window, browse the paleo meal plans hub.

Fasting affects medication and blood sugar. If you have diabetes, kidney or heart disease, take medication or have a history of disordered eating, talk to your doctor or a registered dietitian before fasting.

Paleo and Intermittent Fasting: How to Combine Them, a 16:8 Day With the Numbers, and What the Trials Found