When is a calorie not a calorie?

10. April 2008 William Davis (8)
One ounce of raw almonds (about 23 nuts) contains:


6 grams protein

14 grams fat

6 grams carbohydrate

3.5 grams fiber

For a total of 163 calories per ounce.


(From the USDA Nutrient Database)


Calorie content of foods is determined by summing up the calories from each constituent: 1 gram of fat = 9 calories; 1 gram protein = 4 calories; 1 gram carbohydrate = 4 calories. Calorie content can also be directly measured using a device called a burn calorimeter, in which the amount of energy released from a specific food is measured by literally burning it and gauging precisely how much energy is released.


The problem with both of these methods is that it is assumed that all foods are digested with equal efficiency. That is, it assumes that a potato chip is as readily digested and absorbed as energy from table sugar, a pretzel, oatmeal, a piece of steak, or a handful of nuts. In real life, of course this is not true. Different foods are absorbed with varying efficiency.

For a long time I've suspected that some foods are very inefficiently absorbed. I've particularly suspected that raw nuts are relatively poorly absorbed and thus yield only a fraction of the calories ingested.

Among the studies recently reported at the Federation of the Association of Societies for Experimental Biology (FASEB) meetings I attended in San Diego this past week were several devoted to almonds.

One study, to my surprise, documented this phenomenon. In Manipulation of lipid bioaccessibility of almonds influences postprandial lipemia in healthy human subjects, it was determined that, of 100 calories ingested from the fat fraction of almonds, only about half was actually absorbed. The remaining half passed out in the stool. (They did this by collecting stool samples and comparing the fat composition after eating the different almonds prepartions. This is not discussed in the limited text of the abstract.) In addition, postprandial (after-eating) surges in triglycerides were much less with whole almonds compared to the oil separated from the nut (i.e., broken down into almond oil + defatted almond flour). The researchers attributed the difference to the inhibitory effects of the almond nut's "food matrix," or the structural properties of chewed foods.

Add to this the fact that, of 6 grams of carbohydrate per ounce of whole almonds, 3.5 grams are indigestible fibers. This means that 6 - 3.5 = 2.5 grams of digestible carbohydrates are present per ounce (assuming 100% release).

If we follow the reasoning that only about half the fat fraction of almonds are absorbed, and assume that the protein and carbohydrate (minus the indigestible fibers) are absorbed efficiently (100%), then we would re-calculate the calorie content of almonds to be 97 calories per ounce, or 40% less than calories calculated by composition or measured with a calorimeter.

If we were to assume that protein and carbohydrates were, like fats, inefficiently absorbed because of the effects of the food matrix, then one ounce of almonds yields 88 calories per ounce, or 46% less. This is, in fact, a likely scenario, since the food matrix is largely created by the cell wall and should impede digestive access to fat, protein, and carbohydrate equally.

My point? Almonds and other nuts at first appear to be calorically dense due to fat composition. However, this simplistic view of nuts is misleading because of the confounding effects of the food matrix. Stated differently: Whole foods yield less calories. And, judging by the postprandial triglyceride effects: Whole foods yield less undesirable effects, such as postprandial rises in triglycerides.

Some other observations with almonds included:

The effect of almonds on plasma lipids in persons with prediabetes This study confirmed the LDL-reducing and modest HDL-raising effects of almonds.

Almonds (Amygdalus communis L.) as a possible source of prebiotic functional food This curious observation suggests that almonds modify the bacterial flora of the intestinal tract in a positive way (like the cultures in yogurts).



Copyright 2008 William Davis, MD
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Comments (8) -

  • Anna

    4/11/2008 1:46:00 AM |

    I often soak raw almonds (and other nuts) about 24 hours in filtered water with sea salt, then dry them a day or two at about 150°F in the oven.  I doubt the studies take this kind of "processing" into account, but any idea how that might change the absorption scenario?

  • Anonymous

    4/11/2008 4:27:00 PM |

    I'm glad you posted this.  A few women I know have been wary of eating many nuts for fear that fatty nuts would cause them to gain weight.  

    Really like the little bit on healthy gut flora caused by almonds too.  A healthy gut is important to me.

  • Peter

    4/11/2008 8:19:00 PM |

    I would certainly agree that it is possible to eat enormous quantities of nuts without absorbing all of their calories. I noticed I could remain weight stable while sedentary and eating 3,500 calories back when I used to eat large quantities of nuts. Even when well chewed a proportion of them end up you-know-where! Just flush...

    Peter

  • brian

    4/12/2008 4:22:00 PM |

    Dr. Davis, this is a great example. Thanks for posting it. I have a question on the 88 calories. I tried to work through the calculations to demonstrate this to one of my clients. I couldn't come up with 88 calories per ounce.

    I kept coming up with 80 and here's how. 50% calories from fat is 63. I used 50% for protein and digestible carbs - based on the info provided. For protein, that leaves 3 gms or 12 calories. For carbs, half of 2.5 gms is 1.25 gms, which equals 5 cals. These add up to 80 (63 + 12 + 5).

    I’m probably making a silly mistake but I’d like to come up with the same numbers when demonstrating this to clients – makes me feel kind of silly.

    Thanks again for the blog, I greatly appreciate the information you post.

    Brian

  • Anne

    4/13/2008 9:57:00 PM |

    Does pasteurization affect the positive effect almonds have on gut bacteria? Last year it became manditory that all California almonds must be pastuerized by one of these methods: fumigation with propylene oxide, blanching and oil roasting. This is to prevent salmonella. http://www.almondboard.com/Programs/content.cfm?ItemNumber=890&snItemNumber=450

    I eat a handful of almonds just about every day. I have wondered if there benefits have been compromised.

  • Anonymous

    4/14/2008 12:25:00 PM |

    The study was sponsored by The Californian Almond Association

  • Katherine

    10/21/2008 6:30:00 AM |

    In the era of the 64-oz. soda, the 1,200-calorie burger, food companies now produce enough each day for every American to consume 3,800 calories per day as compared to the 2,350 needed for survival. Not only adults but kids are also consuming far more calories than they can possibly use. http://www.phentermine-effects.com

  • buy jeans

    11/3/2010 6:53:22 PM |

    For a long time I've suspected that some foods are very inefficiently absorbed. I've particularly suspected that raw nuts are relatively poorly absorbed and thus yield only a fraction of the calories ingested.

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Blame the gluten?

Blame the gluten?

14. May 2010 William Davis (17)
Wheat is among the most destructive components of the human diet, a food that is responsible for inflammatory disease, diabetes, heart disease, several forms of intestinal diseases, schizophrenia, bipolar illness, ADHD, behavioral outbursts in autistic children . . . just to name a few.

But why?

Wheat is mostly carbohydrate. That explains its capacity to cause blood sugar to increase after eating, say, a turkey sandwich on whole wheat bread. The rapid release of sugars likely underlies its capacity to create visceral fat, what I call "wheat belly."

But neither the carbohydrate nor the other components, like bran and B vitamins, can explain all the other adverse health phenomena of wheat. So what is it in wheat that, for instance, worsens auditory hallucinations in paranoid schizophrenics? Is it the gluten?

First of all, what is gluten?

Gluten protein is the focus of most wheat research conducted by food manufacturers and food scientists, since it is the component of wheat that confers the unique properties of dough, allowing a pizza maker to roll and toss pizza crust in the air and mold it into shape. The distinctive “doughy” quality of the simple mix of wheat flour and water, unlike cornstarch or rice starch, for instance, properties that food scientists call “viscoelasticity” and “cohesiveness,” are due to the gluten. Wheat is mostly carbohydrate, but the 10-15% protein content is approximately 80% gluten. Wheat without gluten would lose its unique qualities that make it desirable to bakers and pizza makers. Gluten is also the component of wheat most confidently linked to immune diseases like celiac.

The structure of gluten proteins has proven frustratingly elusive to characterize, as it changes over time and varies from strain to strain. But an understanding of gluten structure may be part, perhaps most, of the answer to the question of why wheat provokes negative effects in humans.

The term “gluten” encompasses two primary families of proteins, the gliadins and the glutenens. The gliadins, one of the protein groups that trigger the immune response in celiac disease, has three subtypes: a/ß-gliadins, ?-gliadins, and ?-gliadins. The glutenins are repeating structures, or polymers, of more basic protein structures.

Beyond gluten, the other 20% or so of non-gluten proteins in wheat include albumins, prolamins, and globulins, each of which can also vary from strain to strain. In total, there are over 1000 other proteins that serve functions from protection of the grain from pathogens, to water resistance, to reproductive functions. There are agglutinins, peroxidases, a-amylases, serpins, and acyl CoA oxidases, not to mention five forms of glycerinaldehyde-3-phosphate dehydrogenases. I shouldn’t neglect to mention the globulins, ß-purothionin, puroindolines a and b, tritin, and starch synthases.

As if this protein/enzyme smorgasbord weren’t enough, food processors have also turned to fungal enzymes, such as cellulases, glucoamylases, xylanases, and ß-xylosidases to enhance leavening and texture. Many bakers also add soy flour to enhance mixing and whiteness, which introduces yet another collection of proteins and enzymes.

In short, wheat is not just a simple gluten protein with some starch and bran. It is a complex collection of biological material that varies according to its genetic code.

While wheat is primarily carbohydrate, it is also a mix of gluten protein which can vary in structure from strain to strain, as well as a highly variable mix of non-gluten proteins. Wheat has evolved naturally to only a modest degree, but it has changed dramatically under the influence of agricultural scientists. With human intervention, wheat strains are bred and genetically manipulated to obtain desirable characteristics, such as height (ranging from 18 inches to over 4 feet tall), “clinginess” of the seeds, yield per acre, and baking or viscoelastic properties of the dough. Various chemicals are also administered to fight off potential pathogens, such as fungi, and to activate the expression of protective enzymes within the wheat itself to “inoculate” itself against invading organisms.

From the original two strains of wheat consumed by Neolithic humans in the Fertile Crescent 9000 years ago (Emmer and Einkorn), we now have over 200,000 strains of wheat virtually all of which are the product of genetic manipulations that have modified the protein structure of wheat. The extraordinary complexity of wheat proteins have therefore created a huge black box of uncertainty in pinpointing which protein causes what.

But there's an easy cure for the uncertainty: Don't eat it.
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Comments (17) -

  • lindaharper

    5/14/2010 3:18:04 PM |

    Do you have the same destructive problem making bread from other grains instead of wheat, i.e. rice, barley, spelt? These are all useful for those with wheat intolerance, but I haven't heard you say about using other grains in making your own homemade bread.  I have also read that sourdough leavening is also less destructive.

  • Kevin

    5/14/2010 4:07:03 PM |

    Quote:

    "So what is it in wheat that, for instance, worsens auditory hallucinations in paranoid schizophrenics? Is it the gluten?"

    If wheat is associated with auditory hallucinations, is it also associated with olfactory hallucinations?  I've had them at least 20 years.  For me they go away if I take zinc regularly.  

    kevin

  • Anonymous

    5/14/2010 5:39:38 PM |

    I'd also be interested to know if there is any type of bread (gluten free) which you feel is safe to eat within moderation.

    Rice bread tends to be high-ish in carbs, but at least it avoids the gluten.

    Just wondering if rice bread and other gluten-free alternatives cause small LDL like wheat does.

  • Michael Barker

    5/15/2010 12:51:59 AM |

    What I've never understood is how the Italians have eaten pasta for so many years without, it appears, great problems.

  • Dr. William Davis

    5/15/2010 12:53:57 AM |

    Hi, Linda--

    If you subtract the gluten, you have (mostly) carbohydrates.

    It then boils down to how carb-sensitive you are gauged by, for instance, postprandial blood glucose or HbA1c.

  • Peter

    5/15/2010 11:45:29 AM |

    Another puzzling bit of information is the northern Indians who eat lots of wheat have a fraction of the heart disease of the rice eating southern Indians.

  • Anonymous

    5/15/2010 3:33:12 PM |

    Regarding pasta and Italians -- it was in North America, not Italy, where pasta graduated to main-course portions, probably because it's cheap.

  • Jim Purdy

    5/15/2010 9:24:29 PM |

    "But there's an easy cure for the uncertainty: Don't eat it."

    That makes sense to me.

    But if I have to give up Wheat Chex cereal, can I still eat Corn Chex and Rice Chex?

  • Anonymous

    5/15/2010 11:17:03 PM |

    We've recently gone gluten-free after suspecting gluten intolerance in me and my 3 yr old son. Wow what a difference. After one week off gluten, I gave him one piece of sourdough bread since we were low on groceries and I wasn't able to go out that day. I noticed immediate behavioral changes and changes on his skin (small bumps... my Naturopath says it's a sign he is deficient in certain vitamins, they were going away while he was off gluten). Our lifesavers are quinoa porridge (quinoa, water, milk, egg yolks) and buckwheat pancakes, the kids love them. Makes going grain-free a little easier for my carb-addicted preschooler (we've taken it one step further then gluten-free and eliminated all grains.) Buckwheat pancakes can be used to make sandwiches, as a substitute for bread.  - Valley Mom

  • Chris

    5/16/2010 3:39:29 PM |

    What plant or animal source of food has not been severely manipulated over the last 9,000 years? What if I'm sure I don't have Celiacs Disease or Schizophrenia and I control my daily blood glucose and HbA1C? Isn't wheat just another source of carbs/fiber/protein?

  • Dave

    5/16/2010 3:50:50 PM |

    Just to expand on your last sentence: if there's no upside to eating wheat, and even the remotest possibility of a downside, then the decision is easy.

    Of course there clearly is an upside, or else wheat wouldn't get eaten in the first place. The question is whether or not this upside represents an actual positive impact on health, or a misinterpretation by the brain of signals which normally indicate positive health outcomes. See my blog and ensuing discussion here:

    http://sparkofreason.blogspot.com/2010/05/why-do-you-eat-grains.html

  • Myron

    5/16/2010 6:35:24 PM |

    For People that make excuses or try to talk their way out of avoiding wheat or any other food item, that is the #1 sign of an allergy addiction.

    Take a look at the relationship between low Testosterone and metabolic syndrome and belly fat.

    It's not just a sugar thing, more  related to steroids and stress, IMHO

  • kris

    5/16/2010 8:06:02 PM |

    I do not see a single person around my family who doesn’t have some sort of health issue and they all have northern Indian background. Most of them are diabetics, have heart disease, wheat belly, puffy cheeks, unable to run a mile after the age of 30, hypothyroid, over weight. Just for this topic, if I think about all of the hundreds of people that I know who have northern Indian background, most of them have health issues and they all have high carbohydrate, high wheat based diet. Now there are people within the family who are changing their diet ever since they have seen me improving, about every one of them has made improvements after the change.
    Everyone is entitled to their opinion but,
    I for one believe that the wheat is the one of the biggest culprit in our diet.
    Carbohydrates might be the second in line along with iodine shortages and the list goes on.
    The high glycoside symptoms are very close to the hypothyroid symptoms.
    Every person should own a blood-sugar meter and should have the knowledge to their sugar/carbohydrate reaction profile.
      But I think that finally the time has come where free-will education is being shared in a positive manner which will eventually push the “wanna be Mr Right side” organizations to jump the band wagon sooner or later.
    By the way Dr. Davis, after giving up wheat, taking care of thyroid and weight management which helped me loose 40 some pounds, I am happy to report that after reading your blogs religiously and following that low carb diet, I have lost the last 10 pounds. I have never felt this way in my entire life.
    Keeping my blood sugar level between 4 and 5.5 almost all of skin problems go away which includes but not limited to 10 years old broken hand palm skin, bloody gums, skin inflammation on back of my head, red patch on the facial skin, less bloody shave etc.  Interestingly, if the after meal blood sugar level stays over 6 and around 8 for few days, then most these issues slowly begin to come back. This might explain why I had bloody stomach few years back. Introduction of more fat in my diet may have also helped in all of above.
    All of above is my personal experience so it may not be backed by any study.
    Please keep it up, you are The Doctor.

  • Anne

    5/17/2010 1:21:21 AM |

    Lindaharper - barley and spelt have gluten similar to wheat and need to be eliminated on a gluten free diet. A gluten free diet eliminates wheat, barley and rye and related grains.

    I have gluten intolerance and type 2 diabetes. I can keep my blood sugar in control by limiting carbs. I have not found any grain that will not raise my blood glucose to unacceptable levels. I guess I could eat tiny amount of grain, but why bother. I would rather get my few carbs from highly nutritious low carb veggies.

    Eliminating gluten gave me back my life. Eliminating grains in general further improved my health.

    A great site to read more about gluten is The Gluten File

  • Captain Mikee

    5/17/2010 2:41:49 PM |

    @Jim Purdy: Most breakfast cereals contain barley malt even if they don't have wheat. Barley also contains gluten.

    My family went through a couple months of substituting gluten-free grains before we decided it wasn't worth it and gave up all grains. Gluten-free substitute foods can help you break the addiction, but in the long run I don't think they're very healthy. In fact, in terms of pure nutrition (ignoring the anti-nutrition) no grain can beat wheat. Everything else is worse.

  • Anonymous

    5/20/2010 1:45:25 AM |

    General Mills brand Rice Chex and Corn Chex have been reformulated to remove the barley malt, so they are now gluten-free.  Some (but not all) Erewhon rice crispy cereals are also gluten-free.

  • Aleck H Alexopoulos

    7/20/2010 11:14:29 AM |

    Very interesting information.
    I wonder if there is a compounded problem with fructose consumption.

    I personally believe that we haven't had the time to evolve
    and adjust to the high-carb diets characteristic of agricultural societies.

    Some people are more susceptible to problems of increased carbs, refined-carbs, sugars, and fructose. This susceptibility
    can take a long time to manifest itself. Its not just insulin-resistance, but growth hormone levels, HTA-axis, and other
    hormonal controls but also there
    is a growing realization of the effect of refined carbs and sugars on the inflammation process which suggests connections to atherosclerosis, neuronal damage, and even autoimmune diseases.

    Last note:
    I find it very striking that cancer cells have such a "craving" for sugars that they represent the only cells - other than hepatocytes - that will readily uptake fructose from the plasma.

    Just my thoughts.

    Aleck H Alexopoulos

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