November 16, 2009

Portion Size: Your Brain Is Not Your Friend

As we head into the holiday season it's time to reflect on a food-related issue that doesn't get the respect it deserves: portion size.

A study discussed in Science Daily last spring comes up with a fascinating finding about how our minds work--one that explains why we may find ourselves stalled on diets or seeing inexplicable rises in blood sugar. When presented with pictures of the same food in two different portion sizes, people disregard the differences in portion size when estimate calories. Instead, they seem to take a "unit" approach. One plate of food equals one serving.

The description of this study can be read here:

'Shortcuts' Of The Mind Lead To Miscalculations Of Weight And Caloric Intake, Study Finds

All diet strategies that rely on counting anything will fail if you are estimating counts based on a nutritional database but ignoring the fact that the counts apply to a specific portion size.

Because the portion sizes given in nutritional databases are often much smaller than the portions you are likely to find on your plate you may think you are eating a certain food plan while actually eating two or even three times as much food than you think you are.

This tends to be true of all of us, no matter how aware we may think we are about what we are eating. The best way to deal with it, if you are having trouble controlling either your blood sugar or your weight, is to get yourself a digital food scale and start checking the portion size of the portion you are eating against the portion size given in the reference you are using.

You may quickly find the explanation for why your blood sugar is spiking after eating a food that used to work for you or why you have stalled on your diet.

Portion Size Issues Occur With All Macronutrients

The impact of getting clear on actual portion size will be greatest with foods that contain significant amounts of carbohydrate, because these fluffy foods are often the hardest to estimate. The carb counts given in nutritional guides for breads and cakes, for example, universally use a portion size of about 1.5 ounces for a slice of bread and 2 ounces for a muffin, roll, or piece of cake.

Years ago it is possible that someone did sell 2 ounce muffins, but when I went out last year and started weighing baked goods friends brought over I found that the bakery cookies being sold in my town ranged up to 5 ounces each and the coffee shop muffins were often as much as 7 ounces each. Artisanal bread can easily clock in at 3 ounces a slice, too.

Many people with diabetes can tolerate a 10 g serving of carbs. Some, larger people can even tolerate 15 or 20 grams at once. So if you consult your nutritional guide and see that a single chocolate chip cookies is listed at 9 grams, you may easily end up eating "one" five ounce cookie (or even a "small" 2 ounce cookie) without realizing that the database-supplied carb count was based on the size of one boxed ounce chocolate chip cookie which weighs one half of an ounce--15 grams.

The same is true of pasta. Some people with diabetes can eat pasta, because it does digest very slowly and if they have a slow second phase insulin response, it may be enough to mop up the slowly released carbs. But this tends to be true only if you eat a 2 ounce portion of pasta--the portion listed on the box. The portions of pasta sold at restaurants are anywhere from 6 to 8 ounces of pasta. Far too much for anyone to handle, both in terms of carbs and calories--and we haven't even gotten into the issue of sauce. When was the last time you got 6 servings from one can of bottled spaghetti sauce?

But portion size is not only a problem when you eat carbs. When you eat a very low carb diet, excess protein gets converted into glucose by your liver. So if you are eating far more protein than your body needs to repair muscle or provide the small amount of glucose your brain requires, the rest of the protein you eat will turn into glucose in the liver through a process known as "gluconeogenesis."

This happens very slowly--over about 7 hours, but it can be one reason why people eating low carb diets develop rising fasting blood sugars. If you ate a huge protein portion for dinner, after eating a lot of protein at lunch, the cumulative impact of the glucose derived from that protein on your blood sugar may not show up until the middle of the night. Protein shakes pose the same kind of problem, which is why a diet that involves eating large protein shakes for breakfast and lunch may have a very bad impact on your blood sugar, no matter how "low carb" it purports to be.

Meat portions are very hard to estimate. When I started weighing food a few years ago I found I was almost always underestimating meat portions which could easily be twice as heavy as I thought they were. A 300 lb man might be able to lose weight eating a 12 ounce serving of meat at every meal. A 145 lb woman probably can't.

Fat portions matter too if you are trying to lose weight. When you are eating a very low carb diet it is often possible to eat a lot more fat than you could eat on a standard diet and still avoid weight gain. This is because the processes that lead to fat storage tend to be blocked or slowed down when you are in a ketogenic state.

But if you are trying to lose weight eating too much dietary fat will stop weight loss cold, because it is much easier, physiologically, for your body to burn dietary fat than it is to break down the fat stored in your adipose tissue. So if you are eating more fat than you need, you may see weight loss come to a stop. This is especially likely to happen once you have lost 10-20% of your starting weight--a point at which the body's hormone balance becomes one that is much more conservative about releasing stored fat.

The portion sizes of high fat foods are very hard to estimate because they are so dense. The difference between 1 ounce of cheese and 2 ounces is not a lot. Weigh out one portion of peanut butter as listed on the label you will find realize that most of us eat two "portions" any time we eat peanut butter, if not more, without realizing it.

Be Careful What You Put on Your Plate

The study I alluded to at the top of this post has something else to teach us. Because our brains tend to treat whatever is on our plate as "a portion" it's a very good strategy to make sure that you only put onto your plate exactly what you intended to eat. This really comes into play during the upcoming holiday season where food has a way of showing up on your plate almost as if by magic.

Don't kid yourself that you will only eat "a few bites" of a serving of food that ends up on your plate. You'll do much better if you only put on that plate what you intend to eat. If this turns out to be hard to do--and for many of us it is--if you want to eat "a few bites" of some nutritionally horrifying but emotionally satisfying holiday food, ask a close friend or spouse to take the food onto their plate and then only transfer to your plate the "few bites" portion it is safe for you to eat.

I have on occasion had my Sweetie put overly-appealing holiday food gifts into the family safe and had him dole them out to me on a preset schedule. This can make the difference between enjoying a daily 10 gram treat and experiencing a 100 gram metabolic melt-down.

Planning for the Holiday Food Orgy

When it comes to setting the boundaries, it's worth reminding yourself that no one ever gave themselves retinopathy or caused a 30 lb weight gain eating one special high carb high fat high calorie meal. What messes us up is eating that kind of meal over and over again.

Unfortunately, the holidays we celebrate them now, stretch out into a six week period in which "special" holiday meals can appear daily or even two or three times a day for weeks at a time. And this does pose a serious problem for those of us with damaged metabolisms.

Many of us find that the safest strategy is to plan ahead. We choose the specific days or meals where we will eat whatever we decide we are going to let ourselves eat. These are scheduled events, NOT meals we "schedule" on impulse when confronted with a table unexpectedly loaded with tempting delights.

We prepare for those days of holiday excess by eating very carefully for the weeks before they happen. And we know that we will have a tough day after that holiday feast is done--a day when you will be hungrier than usual and will have to exert some very strong will power to avoid making a "one time" indulgence a daily habit.

If you have run into problems in the past at holiday time, being realistic about what is likely to happen, and planning for controlled indulgence, may work out better for you than resolving on complete abstinence and having the unplanned indulgences overwhelm you.

But if you do end up eating more than you intended over the holidays, don't beat yourself up over it. Only people living in caves with no access to the media who have no friends or family--or whose entire circle of family and friends is made entirely of dedicated health nuts-- get through the holidays without a dietary struggle, and only people with very rigid personality struggles win that struggle easily.

If you do run into trouble, you might find this web page helpful:

When Your Crash Off Your Diet

I wrote it years ago for the general dieter, not necessarily someone with diabetes, but you will find that even if you do not produce insulin it may still be helpful. Since I wrote it I have learned more about the hormonal factors that influence hunger, and I now suspect that these other hunger-related hormones play as much of a role as insulin does in producing the rebound hunger you experience when you eat a lot of foods you've been avoiding on a diet.

But the physiological explanation for the phenomena that occur after you crash off a diet are not as important as is learning a strategy that will keep you from turning a one-time food fest into a month, or year-long binge. The strategies I've described in the web page work very well.

Read the article BEFORE you head out into Holiday Food World. This is definitely a situation where preparing yourself before you get into trouble can make it a lot easier to get out of trouble.



Matt Stone said...

Long-term weight changes cannot be achieved through eating more or fewer calories, so portion size is irrelevant. If you eat small portions, your hunger will increase over time while your metabolism decreases (raising insulin resistance). If you eat large portions, your hunger will decrease as your metabolism rises (decreasing insulin resistance).

Yes, that's right, I said lower insulin resistance eating larger portions. This is one of the greatest flaws of low-carb science (the belief that raising insulin levels after meals causes the 'insulin mechanism to wear out and insulin resistance to ensue.' That's not how the body works at all).

I won't struggle through the holidays because I do not crave unhealthful foods, I no longer have addictive eating patterns, and Thanksgiving dinner isn't much different than my everyday meals.

Jenny said...


You don't have diabetes, so your experience, as useful as it is to people like you doesn't translate.

Many of us, self included have lost significant amounts of weight and maintained that weight loss for many years.

You really need to be more respectful of the needs of the diabetes community before spouting off in places like this blog where the visitors in many cases have a LOT more experience with health and diet than you do. said...

Matt and Jenny, you two are clashing because you're both True Believers and Diet Evangelists for your respective diets.

I, on the other hand, am a Diet Agnostic. As I see things, you're both right -- and you're both wrong.

Of course, even agnostics and atheists succumb to the abundant high-calorie meals of the holiday season.

country mouse said...

I've encountered attitudes like matt's before. I expressed attitudes like matt's before. I call it "one true way" syndrome.

although one thing sets off my bs detector. no unhealthy cravings? sounds unhealthy physically and mentally. dealing with it by a variety coping techniques, yes. outright denial, no.

PJNOIR said...

Between portion size of product and the choice of product in everyday life (ie/fast food, carb rich supermarket items, etc) this is why I call diabetics, a social disease. Its hard to live and eat in a different one (without education).

also- "Stop eating for the poor kids in China." Its okay to leave something behind on the plate. Mom was wrong.

Susanne said...

Matt, you simply cannot understand what it is like to have a metabolic disorder like diabetes if you don't have one. I just turned 53 years old, I am young really, and yet I am struggling for my life already.

My body fights me every step of the way. If I want blood sugars less than 120 in the morning I can eat 8 oz of protein and some non-starchy vegetables for dinner and that is it.

Portion size is hugely relevant to me. When I eat a 22 oz rib eye and a couple of cups of steamed broccoli (low carb, right?) for dinner my blood sugar will be 150 in the morning, or more. If I eat any carb with my protein in the morning, my blood sugars will rise to 180 before they slowly fall during the day.

I don't eat unheathful foods (except for the rib eyes). Trust me, I will not get lower insulin resistance with larger portions (I tried that already). I will not get less hungry with larger portions.

My high blood sugar has nothing to do with addictive eating patterns. It has everything to do with genetics. 3 out of 4 of my grandparents were diabetics, and their siblings were diabetic. My mother, aunts, cousins...all diabetic.

And to top it all off, I am allergic to wheat and most dairy. I suspect my thyroid is failing from a year of drinking low-carb and high soy protein shakes for breakfast and lunch.

I wish I could agree my problems are from low portion sizes and unhealthful cravings, but I cannot. My beta cells are dying. I will end up on insulin at some point, and no amount of eating larger portions of super healthy foods will change that.

ItsTheWooo said...

Hey Matt, are you another one of those guys who wasn't that overweight to begin with, lost about 30 pounds, and thinks he knows everything? Yea, heard it before.

Yes, hunger increases and metabolism decreases when one loses weight. If you figure out a way to prevent this UNAVOIDABLE FACT of weight loss, please do be sure to contact every prominent obesity researcher in the world, they would be interested to hear of your discovery.
I suppose the Matt Stone approach allows one to lose weight without 1) slowing down metabolism or 2) increasing hunger. ITS MAGIC. The secret is to never have been obese, and to just be a vanity dieter who loses 10 or 20 pounds of fat that only ever was gained because of truly abysmal and unnatural eating patterns.

Way too many non-overweight guys online, who were only ever fat because they ate pizza and soda like crazy, who think they understand why people like me are obese as children and get to a high weight of 300 pounds with numerous metabolic & endocrine problems before 20 yeras old. Thanks for telling me that I am all wrong about eating low carb. I'll be sure to make sure to eat lots of carbs and bigger portion sizes to avoid insulin resistance and metabolic slow down. That'll work just as good for my body... (if my goal is to become grotesquely fat, hypoglycemic, insane and afflicted with PCOS again, ha ha).
Oh but lemmie guess the secret to making this work is to do something like avoid fructose, or to exercise an hour every other day, but not cardio just weight lifting, or is the secret this time going to be megadoses of vitamin D?


Out of curiosity have you ever even had a vanity weight problem? Has your philosophy worked for anyone, ever?
I read more about your beliefs here: and you are coming across as quite the nutter.
But I can see how this message would be popular, given the fact that people generally do anything to deny the fact that eating less food/calories/carbs/often protein is typically required of not being a fatass with all sorts of health problems.

Anne said...

When I first went low carb to keep my blood sugar low, I used a scale to check portion sizes. As time went on, I figured I could eyeball how much to put on my plate. Recently I have noticed my blood glucose creeping up and I think it is due to larger servings. I have put my scale back on my kitchen counter and will see if measuring the carbs will help bring down my BG again.

I am not overweight(BMI is 21) but have T2DM controled by limiting carbs.

Thanks for posting about this Jenny.

RLL said...

I almost always bring sucrose sweetened: cranberry sauce, pumpkin cheese cake, and whipped cream. Add lots of turkey, a little stuffing and gravy, plus whatever seems to be low carb, and a few bites (like Jenny) off sweeties plate, and it is a real thanksgiving dinner. BGs do fairly OK.

Stargazey said...

Matt Stone said, "This is one of the greatest flaws of low-carb science (the belief that raising insulin levels after meals causes the 'insulin mechanism to wear out and insulin resistance to ensue.' That's not how the body works at all)."

Really? Do you have refereed journal articles to cite? Or are you one of those who believes that scientists are all part of a big cabal trying to keep truth from the common folk?

Boz said...

With me it's a no brainer. Smaller portion w/ less carbs means lower blood sugar. I can't speak for anyone else, but that's how my system works. And a food scale and measuring cups help a lot toward that end.

William Houser said...

I have kept a record of every meal and its corresponding BG level since I was diagnosed with T2 in April 09. The carb content and the physical volume of the meal are both very important. An oversized portion of salad with a no-carb salad dressing will in my case always cause a spike in BG levels dew the "Chinese Restaurant Effect". I have lost 40lbs.+ more or less as a side-effect
of keeping my BG levels as close to normal as I can. It is not logical to say a metabolic disorder like T2 will be unaffected by the amount or type of food you eat. There is also a big difference between insulin resistance and a lack phase one insulin response. said...

Hi Jenny
thanks for your blog.

I'm not diabetic, but my 2 brothers-in-law (Type 1) and father-in-law (Type 2) are. The eldest brother-in-law is tall and thin, the youngest is tall and b-i-i-i-g, and my father-in-law is tall and developing a pear shape that would put a mandolin to shame. The difference between all three is attributable to eating habits. The eldest eats a healthy diet with small portions, the youngest eats anything and everything with no respect for portions, and my father-in-law eats typically refined and starchy foods and complains all the time about the portion size being too small. He completely eschews wholegrain or slow-to-metabolise fresh food. And of the 3, his blood sugar levels are the most fluctuating, controlled only with ever-increasing amounts of insulin.

While this doesn't constitute a study, it certainly lends weight to your comments about portion size, blood sugar levels, and weight.

My husband and I are a pair of those nutters to which you refer (sorry! :)) ), we honestly enjoy eating stuff which is healthy for us, and we don't miss the junk food. We do eat what we like, but we're so used to fresh and home cooked that we mostly don't finish a portion of dessert if we do want it. We avoid sugar, and our consumption of sugar is in the form of fruit and vegetables. So far my husband is the only one in the family who hasn't developed diabetes, and we believe, rightly or wrongly, it is due to our diets....we are a bit slack with exercise :(

I think it is important to not worry about weight, but worry about health. If a person focuses on putting something into their body which is good for them, rather than counting calories, I think this makes the 'struggle' somewhat easier and over time this becomes a habit and pattern for life.

But then again, we could just be that type of rigid personality having other personality struggles :)