16 8 Fasting Results After 1 Month

What are 16 8 fasting results after 1 month?

16:8 fasting results after 1 month usually show a fast drop in week 1, a stall or small bounce in weeks 2 and 3, and only a modest trend by week 4. In the 12-week TREAT trial, people eating on a 16:8 schedule lost an average of 0.94 kg. The control group eating on a normal schedule lost 0.68 kg. The gap between them was too small to call significant (Lowe et al., JAMA Internal Medicine, 2020).

A flat or wobbly first month is not a sign that fasting failed. It is what the trial data actually looks like.

Why does the scale drop fast in week 1?

Week 1's quick loss is mostly water, not fat. Shrinking the eating window to 8 hours usually means eating fewer carbohydrates in that window, at least at first.

Each gram of glycogen, the body's stored carbohydrate, is bound to roughly 3 grams of water (Fernández-Elías et al., European Journal of Applied Physiology, 2015). When glycogen stores drop, that bound water leaves with it. The scale falls before any fat tissue has actually gone.

This is why the same week 1 drop shows up whenever someone eats less starchy food, fasting or not. It is a real number on the scale, but it is not the number the reader thinks it is. Fat loss in a single week is small next to a shift of a few hundred grams of glycogen and its water.

Why does the scale stall or bounce back in weeks 2 and 3?

Body weight has a normal weekly rhythm that has nothing to do with fasting. In a study of 80 adults with 4,657 weigh-ins, weight peaked on Sunday and Monday. It was lowest around Friday (Orsama et al., Obesity Facts, 2014).

That rhythm reflects ordinary weekend eating and drinking. It applies to anyone who steps on a scale regularly, not specifically to people fasting. A single weigh-in on a Monday in week 2 can look like a reversal when it is just the same pattern every week produces.

Glycogen also refills. A weekend meal with more carbohydrate than usual pulls water back in through the same 3-to-1 ratio, and the scale climbs. None of this means the eating window stopped working. It means one data point in the middle of a month is the wrong thing to read.

By the 12-week mark, the TREAT trial's 16:8 group averaged a 0.94 kg loss (95% CI -1.68 to -0.20 kg). The control group eating on its normal schedule averaged 0.68 kg (95% CI -1.41 to 0.05 kg). The difference between the two groups was not statistically significant (Lowe et al., JAMA Internal Medicine, 2020).

A longer trial tells a similar story. Over 12 months, adding an 8am-to-4pm eating window to calorie restriction produced an 8.0 kg loss. Calorie restriction alone produced 6.3 kg. The net difference of 1.8 kg was again not significant (Liu et al., New England Journal of Medicine, 2022).

So a reader 30 days in, whose trend line is flat or barely moving, is sitting inside the same range these trials measured. Nothing about a quiet first month contradicts what fasting has actually been shown to do.

How much of a month's change could be water, not fat?

The following numbers are illustrative, to show the arithmetic, not a measurement of any one person. Say a 90 kg reader depletes about 400 g of glycogen in the first days of shortening their eating window. At the sourced ratio of roughly 3 g of water per gram of glycogen (Fernández-Elías et al., 2015), that alone could pull roughly 1.2 kg of water off the scale.

Compare the illustrative 1.2 kg of water against the sourced 0.94 kg total loss the actual trial measured over 12 full weeks. A week 1 water swing alone can be larger than an entire trial's net result.

That is the arithmetic behind why a single early weigh-in overstates what is happening. It is also why the trial's real number, spread across three months, looks so much smaller than a hopeful week 1 reading.

Why don't the trials show a big difference from eating on no schedule?

Both trials compared people eating in a window against people eating on a normal schedule. In both, the difference between groups was small and not significant. In TREAT, 16:8 minus the control came out to roughly a quarter of a kilogram over 12 weeks (Lowe et al., 2020).

In Liu et al.'s 12-month trial, adding a window to calorie restriction added 1.8 kg over calorie restriction alone. That gap was again not significant (NEJM, 2022).

This does not mean fasting cannot help someone eat less. It means the window itself is not shown to do something calorie restriction does not already do on its own. A reader whose own calorie intake did not change much across the month should not expect the schedule alone to have produced a big number.

How should I read my own 30-day trend instead of one weigh-in?

A single day's number carries the weekly rhythm, whatever was eaten the night before, and normal water fluctuation all mixed together. A 30-day average smooths past most of that.

The reader comparing "day 30" to an online before-and-after is comparing one noisy point to somebody else's noisy point, not to a trend. The trials above only became meaningful over 12 weeks, not 12 days, and even then the effect was modest.

Plotting a full month of weigh-ins and watching where the line settles is the way to make the number mean something. That beats judging what any single day says. You can paste your daily weigh-ins into the weight trend calculator to see the 7-day averages and a real trend line, instead of judging one day.

What if the scale hasn't moved at all after a month?

A flat line after 30 days sits inside the range the TREAT trial itself measured for its control group. That group lost 0.68 kg over three times that period (Lowe et al., 2020). One month is short next to 12 weeks, let alone 12 months.

A flat first month says nothing definitive yet, in either direction. A recent bounce during the month is also worth checking. It may be a short-term water effect rather than the real trend. The same overnight water-weight mechanism is explained in why a 2kg overnight jump is water, not fat, and it applies to any single weigh-in inside a longer stretch.

A reader curious whether a specific up-swing during the month could be fat can also check how much of a short-term scale swing could be fat with the fat or water calculator.

Avocalo's 30-day weight view sits next to the fasting timer for 16:8, 14:10, 20:4 and one-meal-a-day schedules, so the streak and the trend are in the same place. The app tracks weight over 7 days, 30 days and 3 months, alongside calories, macros, water and activity.

It shows the numbers. It does not tell a reader whether a given change is fat or water, and it gives no medical advice or accuracy claim about the estimates it produces. Reading the 30-day chart with the mechanisms above in mind is what turns those numbers into something meaningful.

Anyone wanting to log meals and track their fasting window and 30-day weight trend can do so in the Avocalo app.

Frequently asked questions

Is it normal to see no weight change at all after a month of 16:8?

Yes. The TREAT trial's own 16:8 group averaged only 0.94 kg lost over 12 full weeks, four times longer than one month (Lowe et al., JAMA Internal Medicine, 2020). A flat first month sits comfortably inside that range and is not evidence the approach isn't working.

Why did I lose weight in week 1 and then gain some back in week 2?

The week 1 drop is largely glycogen-bound water leaving fast, at roughly 3 g of water per gram of glycogen (Fernández-Elías et al., 2015). Weight also naturally peaks on Sundays and Mondays in a normal weekly rhythm (Orsama et al., Obesity Facts, 2014). A week 2 bounce often reflects both effects together, not fat regained.

Does the 16-hour fast itself burn fat, or does the window just mean eating less?

The trial evidence shows eating in a window did not beat eating on a normal schedule by a significant margin. That held over 12 weeks (Lowe et al., 2020) and over 12 months (Liu et al., NEJM, 2022). The window may help some people eat less, but it isn't shown to add a separate fat-burning effect on its own.

How long should I track before a trend actually means something?

Longer than a month, based on the trials cited here. TREAT ran 12 weeks and still found a small, non-significant difference; Liu et al. ran 12 months. A 30-day average is a reasonable start, but a single month is the shortest window worth reading at all, not a rule of thumb for a final answer.

Is a stall in week 3 the same thing as a plateau?

No. A true plateau needs a longer, flatter trend than three weeks can show. Week 3 numbers are still tangled up with the weekly weight rhythm (Orsama et al., 2014) and any recent glycogen refill. Watching a full 30-day average, rather than one week, is the way to tell the difference.

Sources

• Lowe et al., "Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters," JAMA Internal Medicine, 2020: the 12-week TREAT trial's exact kg figures for 16:8 versus normal eating.
• Liu et al., "Calorie Restriction with or without Time-Restricted Eating in Weight Loss," New England Journal of Medicine, 2022: the 12-month trial comparing a time-restricted window added to calorie restriction against calorie restriction alone.
• Fernández-Elías et al., European Journal of Applied Physiology, 2015: the glycogen-to-water ratio behind week 1's fast drop.
• Orsama et al., "Weight Rhythms," Obesity Facts, 2014: the normal weekly weight pattern that explains a mid-month stall or bounce.

This article is published by Petros IT Solutions SRL. See Avocalo's editorial policy for how figures are sourced and checked. Spotted an error? Write to [email protected].