Do potatoes cause weight gain? A longitudinal study following people and their lifestyle choices (foods, exercise, smoking, etc.) so concluded. Theoretical and methodological reasons can be used to dispute their conclusions, since the researchers never investigated cause and effect with a controlled experiment.
Updated: 4 Sept 2014
In an epidemiological study, Dr. Mozaffarian, et. al. (2011) followed 120,877 people over a period of over 20 years to see what they ate and if it was associated with whether they gained or lost weight. They were not obese at the start of the study. Lifestyle factors were also followed: smoking, physical activity, alcohol use, sleep cycle, TV watching. It is an important epidemiological study which helps give us basic information that could help us devise better experimental studies on what causes weight gain. Every four years an evaluation was made. Results: participants gained an average of 3.35 lb every four years which was most strongly correlated with eating potato chips (1.69 lb), potatoes (1.28 lb), sugar-sweetened drinks (1 lb), and meats (0.93-0.95 lb). Weight loss was most closely associated with eating vegetables (-0.22 lb), whole grains (-0.37 lb), fruits (-0.49 lb), and nuts (-0.57 lb) and yogurt (-0.82 lb). [So those commercials are right, after all?] The other lifestyle variables were also associated with gain or loss of weight.
NPR reporter Michele Norris interviewed a member of the research team, Dr. Willett. This study notes that nuts and yogurt were associated with weight loss, but Michele Norris then says that “potatoes of any kind, even just boiling them and eating them plain, caused the most weight gain”. One of the important conclusions that Dr. Willet makes is that fat content doesn’t seem to be associated with whether we gain or lose weight. The study is published in the New England Journal of Medicine for 23 June 2011. See 9news.com for a quick interview and summary.
My Comment Posted at NPR
This study was observation, not experimental and did not study any cause of weight gain. Associations do not define cause and effect. The latter are only hypotheses as yet to be tested. The study also looks to satisfy the original biases that have come down, unproven, to be gospel when trying to control weight: fat and sugar are bad for us. Furthermore, the study did not address motivation. Are people who eat more nuts and yogurt motivated to do so more than those who do not? Or are the people who eat these things less likely to have the damage to fat cells than those who do not may have? Did they control for normal vs damaged metabolism?
All Potatoes are Not Alike
Potatoes do not “cause” weight gain. There has been no experimental study showing such a cause and effect. We cannot make statistical predictions about either one of the associations in this study. Lumping a bunch of foods and drinks together and finding an association between them and weight gain does not mean that if we exclude them from our diets, we will lose weight. Some may, but do they end up losing all the weight they gained since they stopped growing, or reached an appropriate body weight for their build? I think not.
Even though the study categorized all types of preparation of “potatoes” (brand not mentioned), the study was only concerned with how they were prepared. Thinking of the potato as only having a lot of starch probably set up a bias against potatoes and assumed that all potatoes were alike. Nothing could be farther from the truth. We all have tasted a huge difference between Russet potatoes and red or “new” potatoes. They differ from each other in a major way. Russets are in most cases non-organic, or GMO (genetically modified organisms) foods, and thus have most of the boron in them removed, reducing them to a non-soluble, fiber-covered starch nodule with a smattering of magnesium, calcium, and phosphate. They may have antioxidants in them, but these are dismantled when cooked (who eats raw potatoes?).
We are attracted to foods with a particular taste and texture because both sensory information types are critical to guiding us to foods that we need based upon their chemistry. Calcium gives a firmer texture to foods, even the type of pasta we cook varies because the ratio of calcium to boron to magnesium is different from spaghetti to macaroni. We might choose French fries or potato chips because of that extra firm crunch to the texture. Both are made from Russet potatoes, and thus, today, will not satisfy our needs. However the brain doesn’t know that the potato preparation we ate ten years ago is different from the potato preparation we eat now. It goes back to the original taste and feel of the food from the first time we ate it for its recall reference when it scans for possible foods to satisfy our needs.
We keep eating potato chips because of emotional associations with it or because its texture fools our brain into thinking it is higher in calcium than it is. We continue to feel hungry for more because the brain is not satisfied with the chemistry coming into our bodies, but cannot work through the problem found within its own circuits. The potato chips just happen to carry more trans fat or the wrong kind of fat with the calcium. Here is where conscious food choices to prevent us from buying that potato chip bag in the beginning help us to narrow these choices out of necessity.
The study also did not address motivation. What we eat must in some way represent what we need. However, we do not need potatoes or yogurt or nuts. We need the chemical elements and compounds within them, like specific kinds of proteins, or fats, or carbohydrates, or calcium, magnesium, etc. Our conscious brains convert the dots and dashes of chemical needs that the unconscious brain has sent to them for translation to a particular food type. If we want to study weight gain, we have to take into account chemical needs, whole body needs, emotional status, and motivation. Satisfaction (or satiety) rests not only in getting chemicals we need in our diet, but it also means absorbing them, getting them distributed to all the cells that need them, and having those cells produce the metabolites that tell the nervous system that they are satisfied. If we reduce our eating habits to the “calories in = calories out” model, we ignore all of these steps and never solve the problem.
There are specific centers associated with motivation. They give the go-ahead to programs which the unconscious brain has deemed necessary to get a job done. Motivation is not just us hearing that we should eat less fat. Those are external motivations. Internal ones can come from having to respond to craving a food item because it is a comfort food or because we need some chemical, like calcium. Thus a pep talk does little if the chemical or emotional needs are not being satisfied. Many of the foods that make us gain weight might be necessary because these needs are not being satisfied with small portion sizes or with eating other, “safer” foods.
We keep finding out new things about what kind of diet is best, and much of it is very conflicting. We hear that the bulk of our needs are satisfied with fruits and vegetables, but so many people who eat salads all the time continue to gain weight and continue to feel hungry long afterward. Eating whole grains won’t satisfy our cravings even if they make us feel full. One of the newest studies (Bazzano et al. 2014), in a controlled trial pitting low-fat diet against low-carb diet found that those on the low-carb diet for 12 months lost more weight and had lower HDL cholesterol than those on the low-fat diet. The fats did not include trans fats but did include healthy saturated and unsaturated fats. However, Anahad O’Connor, New York Times (2014), warned us that this is not the last word in a “highly contentious” field of research.
See more discussion about the anatomy of motivation in the brain concerning other things, the “Helplessness” section in Physiological Responses to Terror.
Missing the Cellular Level
Most people seem to be happy with just losing weight. So many have difficulty maintaining a diet associated with losing weight for good reason. The problem is associated with the middle of the equation, “calories in = calories out”, or what is happening at the cellular level. Many fat metabolizing cells may be so damaged that we have to eat more fat just to get the energy we need to last until the next meal. We gain weight because our livers and nervous systems say we need to store fat for that purpose. If fat cells in our body core do not respond to nervous system signals, the nervous system thinks they are not there anymore and we need more fat cells. See my post “Cholesterol and Heart Disease” for more discussion about how cells get their nutrients.
Yogurt and Nuts
Nuts and yogurt are two foods extremely high in calcium. Chewing nuts for longer and being able to stay in our stomachs for longer does not make them satisfactory as far the body is concerned. Obviously eating fat is not the issue, since nuts are high in fat–completely negating the dietary rules that some people are pushing on us to follow to lose weight. These rules may work for a little while or cause some weight loss, but will not help us to return to the healthy weight we had when we stopped growing. There are countless numbers of procedures and diet pills for making a person to feel full that work only for a while and only seem to be associated with weight loss up to 20% of the pre-procedure/diet weight level, the amount of weight loss that can be attributed to water loss, but not fat loss.
“Yogurt” that was used in this study was probably not real yogurt because of how it is prepared. Most commercial yogurt has followed the Yoplait model, making creme fraiche and passing it off as “soft” (or “creamy”) yogurt. Real yogurt is left to incubate with the Lactobacillus for 8-10 hours and uses full-fatted milk. Sour cream is made with full-fatted cream in a similar fashion. Creme fraiche incubates full-fatted milk with Lactobacillus for only 2-3 hours. Using Creme fraiche means that “yogurt” companies can make more “yogurt” in a shorter time. Most brands only use low-fat milk. The result is a fairly runny “yogurt” that could never get as firm as real yogurt no matter how long it sits in the incubator.
What many are calling “Greek” yogurt now is what plain “yogurt” is supposed to be–fairly firm, and sour. Of course, most of the Greek yogurt being sold in grocery stores has sweetened fruit added to reduce the sourness. However, some brands have something else to give it that firmness, and it isn’t the additional hours of incubation. It’s gelatin (made from cow hooves, tendons, ligaments, cartilage). Real Greek yogurt is incubated fully, increasing the protein content, produced by the Lactobacillus bacteria. One way that fake “Greek” yogurt can get more protein is from the added collagen fiber in the gelatin, and not from the probiotics mentioned. Another way is to strain the yogurt so that there is more packed into a container, also resulting in increased protein.
The researchers mistakenly believe that the bacteria have an effect on weight gain (but no discussion about how they might cause weight loss). They have no reason to think this. They cite “inflammation” as causing weight gain, and probably think that the bacteria stimulate the immune system to reduce inflammation, forgetting that inflammation is part of the immune process. The inflammatory cycle actually enhances inflammation when the basophils release histamine. Why? Because this inflammation calls out the shock troops–the neutrophils. If inflammation is higher in overweight people, it is more than likely due to the cause of being overweight and that is not because they eat too much. Most likely it is the same cause that severely damages fat cells to no longer metabolize fat. Those likely culprits are toxins. The body cannot get rid of these toxins because the toxins cannot get into the blood vascular system to go to the liver or the liver cannot handle them. Modern life has made enough changes in our environment to cause such damage.
So is “yogurt” associated with weight loss? Or more importantly, how can yogurt help us lose weight? Two ways: calcium and bacterial proteins (Ask Dr. Sears, Fankhauser 2011). Calcium is the magical chemical element needed for all cellular processes everywhere, affecting hormone production, fat metabolism, muscle contraction, nerve transmission. It is so critical that we need it in every meal and almost in anything we eat. Thus, eating something high in calcium tends to satisfy us more quickly than eating something lower in calcium. All dairy products are high in calcium, thus their value in losing weight. If we have a craving for ice cream, drinking a glass of milk or eating cashews (highest in calcium gluconate, the form of calcium that is most easily absorbed and stored in the body), we will suddenly lose the craving for that ice cream.
Yogurt is the same as all dairy products in the calcium it brings to our bodies, but it differs in the type of bacteria it has in it to produce the consistency and sourness in flavor, even from sour cream (Encyclopædia Britannica). The type of Lactobacillus in yogurt is unique and thus produces different proteins when it breaks down milk sugars to lactic acid (Fankhauser 2010). I suspect that these proteins are enzymes that we cannot produce that help to increase metabolism of all cells.
Cheese doesn’t appear to have any association with either weight gain or loss. Again, they are probably tossing all sorts of cheeses into the same category. All real cheeses differ in the type of Lactobacillus and some have bacteria similar to what yogurt has, e.g. port salut (? Don’t remember where I saw this). Most cheeses have bacteria that will do nothing about helping us lose weight. So we can conclude that since cheese is so high in calcium, it might not be associated with weight gain, even though the fat content is higher than is found in milk, or low-fat yogurt.
Nutrition is a Personal Thing
Doctors want to give us advice for losing weight and staying healthy. So they turn to research studies which tell us what an average person in their sample does. Since most of medical research has been increasingly dependent upon observational, and not experimental (clinical) studies, doctors are committing two sins. First, they give advice on research which did not even investigate the cause of weight gain/loss or healthy status. Second, they keep trying to push each individual patient into the same box as the “average” person in a survey who had a good outcome. It is assumed that we all fit the statistical “controls” that researchers impose onto their sample subjects. None of us is average and we each have individual needs that vary from person to person, day by day, and minute to minute. As a result our nutritional needs will vary in exactly the same way. You don’t have to wave your hand and use the “genetics” word, either, because that solves nothing. If we followed our chemical needs when we think of what we eat, we will find that we have far less craving for junk foods.
So how can you do that? We have to use some common sense here. It is obvious that the model that doctors use for determining good nutrition doesn’t work for everyone. We can’t depend upon feeling “full” to know when to stop eating. In fact, many keep eating, despite feeling “full” just because they feel a drive to eat. When someone suggests substituting a high protein food for a high carbohydrate food, it seems to tell us to stop eating after a certain amount is swallowed. They use the same phrase to explain why: we feel “full” sooner, when in fact, we don’t. We feel “satisfied.” Satiety seems to depend not just on how full our stomachs are, but on the nutrient content as well.
I found that using Muscle Reflex/Response Testing (MRT, in a self-testing model) helps to determine what my chemical needs are for that moment. Since the brain keeps a history of what we ate in the past, what our daily schedule seems to be each day, what circumstances we will most likely face each day because of past history, it integrates all that information into a prediction for every meal. It knows that the meal has to supply us with nutrients that we need right now, and will need over the next three to five hours from now. After all, that’s the whole reason for what the parent went through when getting their newborn baby onto a feeding schedule.
We, as humans, do better when we can wait to eat if necessary. It’s better than what a cow has to do, eat all the time. MRT helps us develop the mindfulness that our paleo ancestors probably had about what to eat, when to eat it and how much to eat. When practiced a lot, we train our nervous system (“gut feelings”) to tell us accurately when something is wrong, when our need for food is more of a need for comfort than of nourishment, what we need to eat, how we need to prepare it, and how much to eat. I found that cravings disappeared when I got answers with this method. TV commercials never work on me now.
All this depends upon no other emotional reason sabotaging our body’s needs. Being social animals, emotions have a huge effect on what, why, and when we eat. MRT can help us determine if such sabotage is occurring and, with more detailed questions, why.
So healthy nutrition can only be guided by, not ruled by, the results of research. Our individual needs for low-fat, low-carb, or low-protein diets will vary because our motivation for eating particular foods will vary. Our motivation is not dependent only on the advice we get from doctors, friends, or the need to feel good about our appearance, but also on reasons determined by the brain that depend upon the needs of cells inside the body. If we slant our food decisions toward what our body tells us we need, we will most likely find out that we satisfy our nutritional needs best.
Ask Dr. Sears. 10 Reasons Why Yogurt is a Top Health Food.
Bazzano, L. A., Hu, T., Reynolds, K., Yao, L., Bunol, C., Liu, Y., … He, J. (2014). Effects of low-carbohydrate and low-fat diets: A randomized trial. Annals of Internal Medicine 161(5), 309-318.
Dairy Product. (2011). In Encyclopædia Britannica
Fankhauser, D. B. (12 Jan 2010). Milk Fermenters.
Mozaffarian, D., Hao, T., Rimm, E. B., Willett, W. C. & Hu, F. B. (2011). Changes in diet and lifestyle and long-term weight gain in women and men. New England Journal of Medicine, 364(25), 2392-2404.
O’Connor, A. (2014). A call for a low-carb diet that embraces fat. The New York Times, Sept. 1, 2014.
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