Many of us have a pretty good idea of what to eat to stay healthy (if not, I humbly suggest my healthy eating guidelines for a start)., or the mainstream nutritional advice from my recent post. But actually doing so is easier said than done, because of cravings. I discussed my battle with these in My Eating Story. Cravings can come from two sources, biological and psychological/behavioral, or a combination of the two. I give 3 strategies to deal with them.
Here’s a quick overview, I’ll go into more detail below. Biological sources of cravings could be things like some hunger hormone is out of whack so your brain isn’t getting the full signal, or you blood sugar has dropped too low. Psychological/behavioral could be you’re eating because you are stressed out (“I need comfort food!”) or your food environment is bad, like there’s junk food too easily accessible in your house.
There are 3 strategies to address biological cravings:
- Just stick to healthy eating guidelines. You may have to gut it out for a couple of weeks, But any dysfunction in your metabolism is likely caused by eating our modern overly processed diet. So eating mostly minimally processed whole food and avoiding junk has removed the culprit, and hopefully over time your metabolism will heal itself.
- Transition to healthy eating more gradually. This is suggested by Stephen Guise in his book Mini Habits for Weight Loss.
- Go through a temporary stricter way of eating to “reset” your metabolism. This was proposed by obesity expert Dr. David Ludwig, in his book Always Hungry?. As I mentioned in my eating story, I also kind of blundered into the equivalent of this on my own, and it was helpful for me.
The Biology of Cravings in a Nutshell
So I want to first go over the biological origins of cravings then we’ll get to the details about the remedies.
Cravings have some strong biological origins. There are hormones like leptin and ghrelin that are supposed to control our hunger and match it to our bodies needs for calories. But they are thrown off by eating our overly processed, extremely calorie dense, modern diet. The biological basis of cravings is discussed in detail in Always Hungry?, which goes to the heart of the matter of eliminating food cravings. I am summarizing the discussion here. One of the reasons for the out of whack hormones is that our fat cells become inflamed, or “angry” to use Dr. Ludwig’s phrase. Fat is active tissue which plays a role in hormone signaling, and angry fat send the wrong messages.
This is made worse by not enough physical activity. The majority of Americans are sedentary and overweight or obese, with a high incidence of insulin resistance, or a more serious progression to type II diabetes. This situation is also occurring in many other countries who are increasingly following a modern diet of highly processed food.
[update 03/19/2010: The connection between weight and insulin resistance is weak. Inactivity and poor diet can cause insulin resistance, often before weight gain]
Refined (or “bad”) carbs are a major culprit because they cause a spike in blood sugar, which the body responds to by overproducing insulin, as shown in this figure from Dr. Ludwig’s book.
This sugar spike effect is often pointed out by various advocates of low-carb diets, but they don’t always distinguish between refined and unrefined carbs when discussing this. It was also discussed by Dr. Terry Shintani in his book The Good Carbohydrate Revolution. An important thing to note is that, for the meal with bad carbs, glucose levels go below their original value before eating. This is called “rebound hypoglycemia”, and leads to hunger cravings, often for more junk food.
Your brain can actually think this is an emergency situation because it won’t be getting enough fuel if your blood sugar goes too low, so it pumps out adrenalin. No wonder we get in-between meal cravings. You’re probably going to have trouble fighting off a snack after about two hours or so, and maybe want doughnuts midmorning or “grab a snickers” midafternoon. This will lead to another spike in blood glucose, so the process will start all over again.
Dr. Ludwig explains other deleterious effects on your metabolism in detail, including inflamed fat cells and bad effects on the hormones controlling hunger. I highly recommend reading his book for the fascinating account of how all this works (and for his solution to the problem). It’s also important to point out that these effects, including inflamed fat cells, can occur in normal weight people (who can still have excess belly fat) as well as overweight people.
Approach 1- Just Eat Right And Your Metabolism Will Fix Itself
The obvious answer to all the metabolic issues caused by eating refined carbs seems to be just get them out of your diet. That was proposed in The Good Carbohydrate Revolution and also by various whole food plant based diet proponents (dating way back to Nathan Pritikin in 1979) and Paleo and low-carb authors. It apparently works well for many people. In the figure above, for the meal with no refined carbs, there is no rebound hypoglycemia so there should be no cravings.
I’m sure this will work for a lot of people. The downside is that when you first eliminate refined carbs, until your metabolism is fixed, you’re likely to have a period of cravings, which you may have to “gut through” before you can sustain this clean diet.
Approach 2- Gradual Transition
If you don’t like the sound of “gutting it out” in approach 1, or if you think the reset sounds too drastic, there is the gradual option. The other two approaches are more like diving into the deep end, where this is more like wading in from the shallow end. Stephen Guise wrote an interesting book I recommend called Mini Habits for Weight Loss,, In a nutshell, mini-habits are small changes that are easy to make, and you can succeed at, like replacing your afternoon snack of a candy bar with a piece of fruit.
Using these small changes, you gradually introduce some healthy foods to your diet, which eventually becomes an established behavior, and starts to displace unhealthy foods. This should also over time make your diet more anti-inflammatory and start to address the biological aspects of cravings. I think a good place to start for folks my age would be a mini-habit to eat more berries and walnuts, since these appear to support good brain health as well as other benefits [1,2].
Approach 3- Resetting Your Metabolism
To shorten the period of gutting it out through cravings, Dr. Ludwig proposed a temporary eating period to reset your metabolism to normal, including, as he puts it “calming your angry fat cells”. I highly recommend his book if you want to try it .Just to give an idea, it is essentially a short term use of a moderately low carb diet. You still eat plenty of good carbs but temporarily cut back on refined carbs and starchy foods. But you really need to read the book for the details.
I’ll describe my simplified version here. Remember, I’m an amateur at nutrition, and not qualified to give professional advice on it. I’m just describing what worked for me. If in doubt, please read Dr. Ludwig’s book. The idea is restrict the carb level in your diet by cutting way back on overly refined carbs, which everyone pretty much agrees we should be doing anyway long term. In addition, you temporarily restrict the carb level in your diet further by cutting back on starchy foods. This reduces your overall carb level to a moderately low level, probably less than about 40%. In my simplified version you don’t actually count carbs, but just cut way back on bad carbs, and temporarily also cut back on starchy foods.
First let me point out that this is not the same as the “kick start” that many diet books have. It’s not “go through my one month boot camp and lose 20 pounds to start you on your weight loss journey”. This is to fix your metabolism and you may not have any weight loss at all at first. The first signs of progress are instead starting to enjoy healthier foods and reduced cravings for unhealthy foods.
The “kick start” mentality often fails because of the focus on weight loss. You start with a burst of enthusiasm and maybe get some motivation from initial positive results from the scale, but then get discouraged if the weight loss plateaus or slows down. Also, kickstarts as part of diets often involve calorie restriction, which leaves you physically hungry and can activate the body’s set point mechanism with a vengeance. That’s a tough fight to win.
The reset does not involve calorie deprivation, but instead substitutes eating till pleasantly full with healthier foods. These foods tend to be more satisfying so there’s a good chance you’ll get full on fewer calories, causing weight loss to gradually occur as a byproduct, but weight loss is not the focus during the reset.
I want to be clear about what I mean by refined or processed carbs. I’m mostly referring to junk, like products made with white flour and added sugar (cookies, pastries, etc). I’m not considering frozen veggies or fruit, canned beans or veggies, etc., to be processed. But something like frozen fruit with a significant amount of added sugar would also be considered overly processed for our purposes here.
Ok, finally, here’s my simple version of the reset:
- Be really strict about refined carbs, and limit even starchy unrefined carbs like potatoes, during the reset. Otherwise, eat all the minimally processed whole foods you want. If they don’t provide enough calories to feel satisfied, eat more fat during this time. But it helps to avoid commercial vegetable oils and products made from them, because they have an inflammatory effect on the body, which doesn’t help with healing the biological reasons for cravings. I used extra virgin olive oil (evoo) and organic expeller pressed canola oil.
- Follow this for a minimum of 2 weeks until cravings disappear completely (I was lucky, so for me they diminished right away and were gone after about 3 weeks).
After the reset comes a transition period where you find out what works for you long term:
- Continue long term with being strict about overly refined carbs.
- Next you can experiment with your carb level, by reintroducing the starchy foods you abstained from for the weeks of the reset. You can start with more starchy but low glycemic foods like sweet potatoes or bananas. I personally can also get away with them, and with white potatoes in moderation. All of these are upping the carb content of the diet. If at any time cravings return, back off. If you were not able to add too many carbs back in it might mean you are less carb tolerant, even for good carbs (carb tolerance is discussed below). That does not matter because you can still eat a variety of nutritious foods even if the diet stays moderately low carb, as long as you emphasize lots of fruits and veggies. You just may need to go easy on starchier foods. I did not measure the carbs vs fat when I did this, I just ate till satisfied with plenty of whole food sources of fat like nuts, seeds, avocados. When reintroducing starchy foods I did not cut back on whole food fat sources, but instead cut back on oils.
Hopefully after this reset/transition you will reconnect with your body’s wisdom on how much to eat. You can eat a variety of delicious foods till satisfied, and gradually lose weight if necessary, after which weight management is much easier (because, your body’s set point will lower itself to the new weight). And cravings will be totally gone. I discussed how it went for me previously. I sincerely hope it works out that way for you too! [update 03/10/19: weight loss will not necessarily occur. There is still a strong genetic component. But you will feel better and be healthier regardless of your weight, and eating is much more enjoyable when you don’t have to fight cravings]
You’ve probably noted that following this reset and transition will involve giving up some old friends like soda and your favorite snacks, so it is going to be challenging. To face this challenge, it helps to fix your food environment, and address psychological and behavioral issues of cravings, as discussed in my next nutrition post.
Theoretically, after the reset, with a properly functioning metabolism, you should be able to eat as many carbs as you want as long as they are good carbs (minimally processed and not high glycemic). Some authors, especially of low-carb diets, argue that a lot of people are carb intolerant and need fewer carbs, even good carbs, in the long term.
They assume that if you are currently overweight or have any signs of insulin resistance, it means you are genetically intolerant to all carbs. This seems logical because in recent decades people have started eating more refined carbs, and more total carbs, and a lot more people are overweight. But the percentage of carbs the average American is eating now is actually about the same as in 1900. The percentage went down between 1900 to 1970 and then came back up. But the population of the US was a lot leaner in 1900 even though they ate a similar percentage of carbs compared to today (folks ate the same percentage of carbs then, but a lot less bad carbs, except for white bread) .
There are also two populations that disprove the assumption about genetic intolerance to all carbs: Hawaiians on their original high carb diet were very fit and trim, as reported by early westerners that visited them. The exception were the nobility, who had access to richer foods, and sometimes became obese. Hawaiians on a modern diet have a major problem with obesity and metabolic issues. Yet they can readily lose weight and become healthy if they go back to their traditional diet, which is high in minimally processed carbs (including a lot of taro root) .
The other example is the Native American Pima tribe. They traditionally ate a high carb, whole food plant based diet, very low in animal products, and were slender and healthy. The branch of the tribe on the Mexican side of the border retained their traditional lifestyle and diet along with its good health. Unfortunately, on the US side in Arizona, the Pima were forced off their land onto a reservation and adopted our western diet. They have much higher incidences of diabetes and obesity than the US average, indicating they may have some genetic difference that makes the modern diet extra harmful to them. But an effort has been made to reintroduce the traditional diet to Arizona Pimas, and it has led to remarkable health improvements and weight loss . I would argue that both these populations more likely have a genetically low tolerance for bad carbs, not all carbs.
But there is some evidence for different levels of genetic tolerance for starch . So some people, whose ancestors probably leaned more towards “gatherer” than hunter, may be able to eat all they want of starchy carbs, such as grains, vegetables like potatoes, and fruits like bananas, while others may need to consume these more moderately but can still eat all they want of non-starchy carbs.
Carb tolerance, even if it has a genetic component, is probably not “carved in stone”. Resetting your metabolism should improve it, as will losing weight. Adding physical activity if you are sedentary is also known to improve it. There are healthy populations that eat up to 80% carbs as I’ll describe in a future post. They are all very physically active. [update: 03/10/2019: The connection between weight and insulin resistance (and therefore carb tolerance) is weaker than I knew when I wrote this]
You can find out for yourself what your carb tolerance is during the transition described above. As long as the level of good carbs you are eating does not cause cravings to return, you are fine.
Good and Bad Carbs: Glycemic Index/Glycemic Load
Measuring the glucose vs time graph shown in the figure above allows us to determine how good or bad the carbs are in various foods by quantifying the “glucose spike”. The amount of sugar in the blood two hours after ingesting 50 grams of a specific food is used to determine the glycemic index or GI (it’s the area under the glucose vs time graph at 2 hours, for math nerds like me). So low GI is good, high is bad. GI works great for most foods, but is misleading for some, like carrots, for which 50g is a very large serving. So in my opinion glycemic load, or GL, is a better measure, because this factors in the number of carbs in the actual serving of food. So the formal definition of a “good” carb is one with a low enough glycemic load, while a bad carb has high glycemic load.
You could actually use a chart to check all your foods, but this would be tedious. I think it’s enough to keep in mind what the potential problem foods might be, which are all refined foods, plus some starchy fruits and vegetables and some grains. White potatoes have a higher GL than sweet potatoes, for example.
When in doubt, for a borderline food, The Good Carbohydrate Revolution recommends keeping GL under 20, and has an extensive chart. It’s still in print in paperback. There is also a list in Always Hungry? It’s not like you’re going to fall off a cliff because you ate one baked potato. But If your cravings come back, maybe consider what you ate recently, and avoid or cut back on the likely culprit.
- Devore, E, et al, “Dietary intakes of berries and flavonoids in relation to cognitive decline”, Ann Neurol., 2012
- O’Brien, J, et al, “Long-term intake of nuts in relation to cognitive function in older women.”, J Nutr Health Aging, 2014
- Gortner, W, “Nutrition in the United States, 1900 to 1974”, Cancer Research, 1975
- Shintani, Terry, The Good Carbohydrate Revolution, Atria, 2002
- Ravussin, E, et al, “Effects of a Traditional Lifestyle on Obesity in Pima Indians”, Diabetes Care, 1994
- Perry, G, et al, ,”Diet and the evolution of human amylase gene copy number variation”,Nature Genetics, 2007