Why Drop Carbs and Eat More Fat When Adapting to a Fasting Lifestyle?

By Jay Richards Published on March 3, 2018

This is the eighth piece in a series on how to develop a fasting lifestyle. Read the entire series here.

The first week of our plan allows you to slowly shift from a sugar-burning to a fat-burning metabolism (called ketosis), which is the gateway to successful fasting.

Our bodies have two distinct ways of converting food to energy. But most of us haven’t really used the fat/ketone one much since we were infants. We subsist on the carbohydrate/sugar cycle, which makes fasting hard. That’s because it has to be recharged every few hours. And when it’s running, the fat/ketone pathway is mostly offline. Our body is like a hybrid car with a backup gas supply that never gets used because the power charger is always nearby.

For the most part, these two systems don’t run at the same time. As long as you’re eating lots of carbs — especially carbs with a high glycemic load — your body will just stick with sugar burning and store any extra as fat. Think about that. Your body will hoard extra energy from your food as fat on your liver, in-between your organs, on your belly, hips, and thighs. But it won’t be able to use it. No one would do this on purpose. Because of the flood of bad dietary advice, though, many of us do this while trying to do the opposite.

As mentioned in the previous piece, this process is controlled by insulin, a hormone released by your pancreas. Insulin’s job is to keep your blood sugar levels from getting too high. It tells your body whether to store extra sugars and fats as body fat, or to burn fat from your diet and fat stores for energy. If you eat a lot of simple sugars and processed carbs over years or decades, your insulin levels will never get very low. As a result, you could very well become insulin and carb resistant. That means your pancreas has to keep pumping out more and more insulin to clear sugar from your blood.

Think of that insulin as a signal telling every cell in your body: burn sugar, store fat.

Why Two Systems?

Why do we have two systems then? Because we’re designed to survive in different places. For most of human history, people have had to survive lean times and fat times. That’s why people can live on every continent on earth and get by with diverse eating habits. (The 3 meals a day routine is not universal.) Polynesians can do just fine eating fish, coconuts and breadfruit. The Maasai do fine on little more than milk, meat and blood from their cattle. Inuit tribes, and Scandinavian scientists who study them, can prosper year round on little more than blubber and meat from whale and seal.

For thousands of years — outside the tropics at least — people had to endure gaps in their food supply. That means that they had to spend at least some of the time running on fat, which makes sense. Fat is more energy-dense than the other two macronutrients: carbohydrates and proteins.

Every so often, if they were lucky, our ancestors gorged on sweet berries and an unexpected store of honey. This allowed them to build up some body fat, which they then used when the berries, honey bees, and other foods became scarce.

Agriculture brought a steadier supply of grains. Except for some honey, however, no one ate concentrated forms of sugar or highly refined carbohydrates every day. That’s a modern mistake.

These days, we live on sugars and simple carbs (which our body quickly converts to sugar). So, unless you go out of your way to tap the fat-burning system, you probably won’t. The fat on your body will be like guests in Hotel California. They can check out any time they like, but they can never leave.

Fasting for Body and Soul Jay Richards 2 - 600

Fasting and Feasting

Fasting, with a feast every so often, mimics this older, natural pattern. It allows us to use both systems. It harnesses our natural design plan far better than the common modern diet, which has created what some call “diseases of civilization”: obesity, high blood pressure, insulin resistance, inflammation, Type 2 diabetes. Insulin injections treat the symptoms of Type 2 diabetes. But as the body becomes more insulin-resistant, it needs more insulin, and the problems get worse and worse.

Most of this diet damage has happened in the last sixty years. It’s gotten even worse in the last thirty years, since government started to push high carb, low fat diets. Type 2 diabetes used to be called “adult onset diabetes,” but more and more kids are getting it. Just from 2000 to 2007, diagnoses grew by over thirty percent!  And some one in three adults is pre-diabetic.

The plan I’m describing should allow you to get this fat-burning system up and running. And that, in turn, will make regular fasts — from 24 to 72 hours and more – easy.

Depleting the Sugar

Over the first few days of week one, you will deplete the stored sugar (glycogen) in your muscles and liver. Your body will use hormones to keep your blood sugar stable. To do this, it will start using extra proteins and amino acids to produce sugar (glucose) in a process called gluconeogenesis. (Literally: creation of new glucose.)

Soon, though, your liver will start converting your dietary fat to a different type of fuel, ketones. There will be bumps and starts as the new system comes online and your body gets used to the other system. Don’t forget the extra water and salt.

If you work out hard, you might even deplete your glycogen stores and start producing ketones in as few as forty-eight hours.

Why Do I Need to Eat Fat?

But if severe carb restriction (below 50 grams a day) forces your body to start turning fats into ketones, why eat so much fat? Why not just eat protein and wait for your body to start burning body fat? If you’re already insulin-sensitive and metabolically flexible (more on that later), that strategy might be okay. But, remember, protein raises insulin. So, eating nothing by protein is not a good way to turn on the fat-burning system.

Besides, most folks’ bodies aren’t used to using fat stores for energy. In that state, a very-low carb, low-fat diet is too much like starvation. If you cut protein too, then it is short-term starvation. Remember, our goal to make real fasting part of our everyday life, not suffer starvation. So, it’s much better to give your body extra dietary fat while it’s adjusting to its alternate fuel source.

Again, take a cue from Lent, which lasts forty days.

In the next installment, I’ll describe week two.


Jay Richards, PhD, is the Executive Editor of The Stream and an Assistant Research Professor in the Busch School of Business and Economics at the Catholic University of America. Follow him on Twitter.

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  • Hmmm…

    Started reading the book I ordered on this, along with more of these articles. It’s hard when some regular food is off limits — like root vegetables, grains and such because they are starches. No more carrots, potatoes? No oatmeal? Going back to bacon and eggs for breakfast? I’ll never eat pork again, so I have found a vegetable base bacon that suits the best: Morning Star’s, but hmmm …. It takes a while to get the concept, so continuing on with that.

    • Paul

      “It’s hard when some regular food is off limits…”

      Yea, the mental shift takes time to adjust to the new regular, especially in a culture pushing carbs on us from every direction. I used to eat cereal or oatmel with fruit for breakfast…carbs with carbs… had that starving feeling every morning and dove right into that morning big bowl of carb fix like a junkie, sometimes two. Now I’m rarely hungry like that waking up since I didn’t eat much carbs the day and night before, haven’t had cereal or oatmeal in well over a decade.

      • Hmmm…

        Did you find yourself working on the big picture at first, if you can think back after having done it so long? You kind of have to see your way right? In the book, they have recipes and online, of course, there are tons, and he says if you eat these meals, you will be there. It’s being able to figure out what to do that doesn’t just hop into your brain, so having menus helps. I was on a ph balance, alkaline, non acidic type eating program for decades, and this contradicts some, especially so much meat. It’s a process like anything.

        • Paul

          Yea, we mostly cut rice and corn also being grains.

          Todays breakfast was a 3 egg omlette with turkey, would have added some spinach and cheese but was out. Also had some smoked salmon.

          I stopped having caffein years ago so only drink water and sometimes decaf tea or wine…but not with breakfast lol.

          Over the years we’ve accumulated a lot of books on Paleo cooking, there really is a lot of variety, it just takes time to adjust your mind and especially the pantry.

          A note on Paleo, if you look into it you’ll find a lot of talk about human evolution, as a creationist I ignore that part and give credit to God for how He designed us. That being said, it is less a ‘diet’ and more a new way of thinking about food and lifestyle. Lots of delicious recipes but mostly eliminating grains and focusing on meats, vegetables and fruits, the amounts of which can varry seasonally and also depends on your needs and goals.

          • Hmmm…

            Thanks much

          • David

            It’s hard but it’s worth it. I have lost 112 pounds since last July! ‘if it doesn’t challenge you, it doesn’t change you ‘

          • Hmmm…


    • Az1seeit

      This concept is the foundation of the Atkins, Protein Power and other low-carb diets out there. You are exactly right that the initial phase is hard…but you must remember it is temporary. In the large scheme of things, one week of less than 50 carbs a day…or less time, depending on your own body…to turn yourself over to fat storage burning is a small price to pay for an almost effortless future of healthier eating. Afterwards, your body no longer craves the starchy carbs, and you can easily diet until your weight goal is met. Even then, if you add in some starches, you don’t need much to satisfy you. It’s win-win for me,

      • Hmmm…

        Very encouraging; thanks so much.

        • Az1seeit

          In the end, it’s what works for the individual. This concept works for me as long as I actually follow it.

        • Paul

          Protein is certainly found in plants, not just meat, but herbivores have a digestive tract designed to maximize that diet. We’re designed differently.

          • Hmmm…

            Yes, but we don’t need near the protein that has been hyped in the past. As you say, the plant based protein will do it. How are we designed differently from herbivores? We started out plant based … And, aren’t vegetarians healthy? There’s a good case for meat being accountable for a lot of disease, and the struggle for good, clean, even koshser meat is one not everyone has time or can afford to take on.

          • Paul

            Well an easy example is a cow having 4 stomachs to digest the grass it eats. We wouldn’t fare that well on that food source but cattle thrive.

          • Hmmm…

            Hmmm … we don’t eat grass and attempt to digest it. Again, vegetarians seem to thrive. I’m not at all sure we need meat. Man did not eat it in the Garden of Eden. It was only after the flood that Noah’s family ate animals because almost all the vegetation was gone. After it grew back, man continued to eat meat. The dietary laws are severe on meat, draining the blood and all that. We certainly don’t need the huge amounts most Americans consume.

          • Paul

            low carb/high fat diet is doable as a vegetarian, especially since they often also eat eggs and dairy. More challenging I would think is for vegans who avoid all animal products. I’ve done neither so can’t speak from experience. If you search “vegan low carb high protein foods” you can find some more info.

            Regarding the Garden of Eden, I can’t begin to imagine it, a perfect environment for us, wish we were there but we’re not. I wonder how disgusting our best fruit tastes in comparison to what Adam and Eve ate there. But we’re now fallen people in a fallen world.

            There are cultures who traditionally subside almost exclusively on animal products. but I’m not aware of any that were exclusively plant based. I don’t claim to know all cultures in human history, just saying I’m not aware of any, except of course todays vegetarian and vegan adherents, and every one of them that I personally know do so from an animal exploitation perspective as opposed to seeking superior nutrition. Perhaps there are those who do that, I’d be interested to hear their arguments and evidence.

    • Andy6M

      Can I ask why you won’t eat pork products? Honest question asked out of curiosity.

      • Hmmm…

        Sure – the high cholesterol, that pigs are part of the garbage cleaners of the animal chain, eating anything, unclean in Biblical law for a reason, that something happens in digestion with pork that heats up internally something, sorry, but those are enough for me.

        • Andy6M

          Fair enough. I’m from Canada, so I don’t know if this suggestion will help you (not that you need help either), but we can get a turkey bacon up here that we really enjoy. I’m not a turkey bacon fan but have loved this stuff from the first time we tried it. They call it “Day Starters” and it’s from a company called Lilydale. Might be worth a search.

          • Hmmm…

            Yes, we have many turkey bacon, sausage, burgers and other products and vendors. Most is good, and I make use of it! I’ve liked Butterball; Morning Star has the best tasting veggie bacon, but they do use soy. Your product is not sold in my area, and ordering online is beyond a fit for time and money. thanks

  • NellieIrene

    This sounds like Atkins. High protein and fats doesn’t seem like it should work. But I do Atkins whenever I have a few pounds to lose and it does work. And fairly quickly.

    • Jay W. Richards

      It’s similar but ketosis requires lower carbs than even the regular Atkins diet. Also, you have to watch protein intake as well, whereas Atkins tended to treat protein as neutral.

      • Paul

        IIRC Atkins induction (phase 1) targets about 20 grams of carbs/day for a few weeks which gets a person into ketosis. Maintenance moves up to 100 grams which stops it which can set some people back.

  • David Reinwald

    I’m starting a 3 part sermon series in my church tomorrow utilizing this great information. I’m loving this series! Went HFLC (High Fat Low Carb) about 5 years ago when I discovered hardening of the arteries. I’m very excited to see the correlation between this lifestyle and biblical fasting.

    • Jay W. Richards


  • DigitalDeb

    This is all what Dr Jason Fung’s podcasts discuss. He’s currently got two books out, The Obesity Code (also the name of his podcasts/check YouTube) and The Complete Guide to Fasting. He’s a Canadian nephrologist who uses nutrition to help his struggling T2D patients with insulin resistance. My son discovered Keto about three years ago and dropped 75 pounds, reversed his fatty liver and pre-diabetes. Now that he is able to exercise regularly, he eats clean and he now understands the balance that healthy food, intermittent fasting and exercise does for his body. His success spilled over to his sisters who now have healthy lifestyles with keto eating comingled with intermittent and extended fasting. I was naturally on that path as I’m Celiac…no wheat, corn, rice, soy or dairy. I immediately lost 45 pounds of inflammation within the first 5 months of my diagnosis. I tend more toward keto eating myself. My homocysteine level came down from 15.1 to normal 8 (the better predictor of heart disease) and my HSCRP came down from 4.1 to .03. Food is fuel. You have to be open to changing how you think about food. Listen to Dr Fung’s podcasts and The Two Keto Dudes as well. Lots of motivation to get well, heal your body, get off medications and get your life back! Be well!

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