How To Do Intermittent Fasting for Weight Loss?

How To Do Intermittent Fasting for Weight Loss? When I’m out and about in the community, people ask me nearly constantly how to do intermittent fasting and, more pointedly, how to get started with intermittent fasting for weight loss. What to eat? When to eat? Here’s my basic blueprint.

Intermittent fasting for weight loss is basically just a structure of eating in which you eat in a specific “window” of time during the day and you “fast” for the remainder of the day. During my eating window, I eat a meal that is very low in carbohydrates (“keto” even) and high in vegetables. I stay in “ketosis” all the time, a “fat burning” mode, because of the low carbohydrate diet but the eating window itself IS the “intermittent fasting” aspect of my plan. I see the intermittent fasting for weight loss as containing two key parts:

  • A short eating window — one hour out of 24 hours in my case.
  • A low carbohydrate, keto diet high in nutrients during the eating window. (More on the keto diet for weight loss.)

I expect both what I eat and when I eat it have been key factors in my rapid weight loss. I am also fully aware that my approach is pretty hard core, born out of sheer desperation, and that most people are not going to do exactly what I am doing. That’s OK: I expect any sustainable eating model needs to be customized anyway to fit our own lifestyles. You need to find what works for you.

So how to do intermittent fasting for weight loss in a way that works for you and your specific weight loss goals?

I recommend to people that they think about both aspects of the approach and rein both in a bit.

How To Do Intermittent Fasting: Implement an Eating Window

You can eat two meals in 5 hours. My husband lost 15 pounds in one month eating two low carb meals a day in five hours. If that seems highly restrictive, you can eat three meals in 8 hours. I expect most of us can survive well and pretty easily eating in five hours even though, at first, it seems very difficult. We have been programmed by our culture to eat little meals throughout the day, so this “eating window” idea is certainly new, but I was surprised to find out how easy it was to implement once I actually got started.

You may be on medication requiring you to keep a 5-, 8-, or 12-hour window. If you must have an 8-hour eating window for your own reasons, then by all means, do what you need to do but then be strict within that framework. You can do it!

The Food You Eat When You Are Intermittent Fasting for Weight Loss: Keto for Fat-Burning

When you break your fast, you need to eat healthy, whole foods. For rapid weight loss, those foods need to keep you in ketosis so that you are burning fat and not just living off food sugars.

If you are eating the standard American diet now, you need to rein in your carbohydrates and get them down into the keto range. This will likely feel more restrictive than the eating window and don’t feel bad if it takes a month or longer to make the transition, but get started. Rein it in.

In my case, my carbs stayed under 20 net grams a day and I stayed in ketosis constantly during my season of aggressive weight loss. You may be able to eat more carbs and stay in ketosis. We are all a little different.

A useful tool in this regard are the keto urine sticks which show color when you’re in ketosis. (You can find them here through our Amazon partner.) When I started the diet, I used the sticks a couple of times a day to watch my descent into ketosis. (It took 2 days for good color to show on the stick and 3 days for a very dark color.) At times when I am not sure if I’ve blown my keto plan, I’ll use the sticks just to check. These aren’t highly accurate measurements but, on the whole, I find them useful tools. I do notice a color change based on my own eating behavior and, I expect, in the main, the sticks are reasonable measures of whether you’ve blown the diet with some sort of mystery ingredient at a party or a restaurant.

When you are first transitioning your eating and still eating a relatively high number of carbs, you will show no color on the keto sticks. It takes some real dedication to get into ketosis. As you transition, I would just focus on issues of giving up the sugar and other goodies that are going to keep you from your goal. As you approach keto-level carbohydrates, you might bring in the test sticks as an additional tool.

Reign It In and Monitor Your Weight Loss Progress

Reign in the carbs and reduce your eating window. Watch the scale in the process if you are working on weight loss. If you’ve made real changes on both of these dimensions, you should see changes in a couple of weeks if this program is going to be effective for you.

A family member implemented an 8-hour window and reduced carbs but was not in ketosis. She lost five pounds in two weeks. She could probably lose more faster if she could get in and stay in ketosis. That said, five pounds in two weeks is stinking fantastic!

A friend lost eight pounds in one week (!) reducing carbs and implementing a short eating window one day and a longer window the next. He ate one meal every-other-day (an “Amanda salad meal” he calls it) and on alternating days, adding a meal that was typically a steak and vegetables. He could lose more pounds more quickly by being more restrictive but he obviously doesn’t need to and it is probably just as well he didn’t go through the pain of going all hard core. He landed on a model that works for him.

In both of these cases, they were monitoring their progress and now have a sense that the structures of this way of eating DO work for them. They can get more or less strict depending on their goals but they now have useful information to help them manage their weight. That’s exciting!

You can do the same thing. Reign things in, watch the scale, and see how it goes. Get more strict if you need to. Scrap the whole thing if it doesn’t work for you. In my experience, intermittent fasting for weight loss has been a pretty slick tool for many, many people. You may be one of them.

Cautions with Intermittent Fasting for Weight Loss

We all have different health starting points. If you have a more complicated health situation (and even if you don’t), you want to do a check-in with the doc. We have many people in the Eat Like A Bear! group who are on medication for diabetes and for high blood pressure. Those members in particular are working with their doctors regularly (even weekly in some cases) to monitor their medication. Why? (Wait for it…) The diet is working so well for some people that their medications need to be reduced. They know they need to be reduced because they are monitoring their cases. Their doctor helps them reduce their medications so that they are essentially not as risk of over-medication. As you lose weight, it is likely that your blood sugar and blood pressure will actually improve, independent of the medication. If you are taking too much medication, your blood sugar or your blood pressure could actually reach dangerously low levels. That is why you and your doctor are monitoring them. These are the most common examples of dieters working with their doctors. I highly encourage you to do a check-in if you are following intermittent fasting for weight loss. (Pro tip: Don’t call your diet “intermittent fasting” or “keto.” Tell your doctor you cut all sugar and starches and are only eating one (or two) meals a day. Keep it descriptive and honest but avoid the increasingly loaded diet labels from internetland. Very few doctors would disagree with eating a limited number of low-sugar meals. In fact, I expect the number of doctors approaches zero.)


  1. This seems doable…I am the one struggling with my weight. My husband is not…so I do worry that our "time eating together" will suffer.
    But, taking off 80 pounds is more important ‼️ For both of us‼️

    1. You’ll find a groove with all of that too, Paula! I actually often sit with my guys while they eat. You just find a new rythm

  2. I have recently lost 35 pounds doing a keto intermittent fasting. I have struggled since Thanksgiving the more the scale goes up the more depressed I get. I’m 59 I’m in pretty good health. My mom is 90 and is in very good health and I would like to be able to be active if I’m going to be here that long. I am also a truck driver so I am sitting most of the day. And I work night shift. I am new to working night shift since August. That has really put a lot of unnecessary pressure on my body. So I’m trying to find something to fit in my lifestyle. Starting back up on the intermittent fasting I will probably start with a five hour window. I’m looking forward to not doing it alone. I am setting my goal for 20 pounds and I will adjust when I get there.

    1. I’m flexible in my maintenance, but do find one meal much easier in times of stress (when I am more likely to regain)

Leave a Reply

Your email address will not be published. Required fields are marked *