Susan sat across from me and I could see her chin quivering as she tried to hold back the tears.
“I am trying so hard to lose weight, doctor! Look at my diet diary. I’m at the gym almost every day. My thyroid numbers are perfect. And so what happens? This past month I actually gained three more pounds!”
Having battled weight issues myself since age seven, I could truly empathize.
And really, for decades physicians and nutritional scientists have spent countless hours combing through data or in laboratories and clinical research centers trying to find an answer to this maddening problem. Why does Susan, and millions of people like her, apparently do everything right for effective weight loss and either remain stuck at an undesirable weight or actually see that ominous number rise?
For years the gold standard for weight loss, delivered by the Endocrine Society, was “Calories in, calories out,” also known as “a calorie is a calorie.” I well remember hearing variations on this theme: “You can eat a 1000-calorie hot fudge sundae every day, limit yourself just to that, and if you’re burning 1500 calories you’ll lose weight.”
Fat calories, sugar calories, protein calories. No difference among them, so they said. If Susan wants to lose weight she should eat even less and exercise even more.
A tidal shift with CIM
On July 2, 2018, the Journal of the American Medical Association (JAMA) issued a “Special Communication” to all of America’s physicians. This is not an everyday event, and when I saw the subject was obesity, I figured many of you might be interested.
Lock these three letters into your brain: C-I-M.
CIM stands for the Carbohydrate-Insulin Model and while you can plow through the article, if you bear with me I’ll try to explain Susan’s predicament (and perhaps your own) in CIM terms.
America’s serious weight issues really began in 1970. Being overweight myself back then, I knew from my internal medicine training that I should simply eat fewer calories. I also knew I should avoid fat calories because doing so would get my weight down and keep the evil cholesterol at bay.
It made perfect sense at the time. Fat has concentrated calories (9 calories per gram), while protein and carbs have less than half that amount (4 calories per gram). The butter on your pile of mashed potatoes was the villain, not the potatoes themselves.
So we’d tell our overweight patients to trim the fats away, which meant they’d be eating more carbs. At the same time, foods themselves were changing. During political issues with Cuba, we banned cane sugar and gave the corn lobby carte blanche to add corn syrup to everything from Coca Cola to ketchup. The more they sweetened our foods, the more we became addicted to sugar. Sensing this, food manufacturers increased the sugar content of everything in sight.
Our sugar intake had already grown from a mid-19th century 15 pounds of sugar per person annually to its current 155 pounds per person every year (almost a half a pound of sugar a day!). Add to this the naturally occurring sugars in fruit and the sugars that appear when we digest processed grains, starches, and simple carbs.
Under the Carbohydrate-Insulin Model, the tsunami of sugar pouring into your body has a terrible effect and is probably responsible for Susan’s weight issues and those of millions of others.
Here’s what happens in the CIM
Well-intentioned Susan has just eaten a low-fat blueberry muffin. She feels good about this because it contains a mere 3 grams of fat, though she’s not quite sure how to interpret that it also contains 47 grams of sugar. This is nearly 10 grams of sugar more than a can of Coke contains.
Whenever Susan eats something that raises her blood glucose (sugar), her pancreas starts pouring out insulin in an attempt to lower it. And we now know that in the process of attempting to lower glucose, Susan’s insulin does several other things:
–Her insulin actually changes the way these calories are used as fuel. This is key: The more insulin present, the fewer calories will be burnt as fuel.
–What happens instead is that the excess insulin actually drives the glucose into her fat cells and interferes with the way fat cells should burn fat as fuel. Instead of helping to burn fat, insulin promotes permanent fat storage.
–But because insulin drives down blood sugar, Susan quickly finds herself hungry again. This means that having chowed down on the low-fat muffin, two hours later she’s ravenous.
From a physician’s perspective, this phenomenon explains why patients with the excess insulin of Type 2 diabetes (what used to be called adult onset diabetes but now affects children too) generally gain weight and why patients with the lack-of-insulin diabetes (Type 1 or juvenile diabetes) are usually underweight.
Fast carbs turn to sugar
Among the many influences on insulin secretion, dietary carbohydrates have the most profound effect, and of these the worst offenders are those that convert quickly to sugar. You know these as “fast carbs” or foods with a high glycemic index (GI). Refined grains (bread, crackers), potato products, and anything with added sugar digest quickly into pure glucose (sugar). These high-GI foods stimulate insulin production, which triggers increased fat storage and slows fat-burning systems.
When it comes to other foods and insulin production, we get a different picture altogether. Truly whole grains (such as barley, quinoa, millet, wheat berries, and wild rice), non-starchy vegetables, and many whole fruits are all low-glycemic choices that have some effect on insulin production, but nothing like the high-GI offenders. Protein-rich foods stimulate insulin, but some of protein’s amino acids (protein building blocks) cause the pancreas to release an antagonist to insulin called glucagon.
Ironically, fat, the nutritional Darth Vader of the past half century, has almost no effect on insulin production, conferring physiological confirmation of the weight-loss effects of various high-fat diets (RIP, Dr Atkins, you were right all along).
Under the CIM model, being overweight is not caused by overeating per se (hence Susan’s dilemma), but rather that inadvertently her dietary choices are increasing fat storage, slowing fat burning and making her hungrier in the process. Our modern food environment almost dooms us from the start. If we eat mass-produced food, our bodies will take what we give them (lots of simple carbs) and produce more glucose and then more insulin. This is followed by more fat storage and less fat burning.
Without actually calling it the CIM model, this low-glycemic program is what our nutritionists Marla Feingold and Olivia Wagner have been recommending to patients all along. However, as Marla will be happy to tell you, old habits die hard. A well-known statistic is that during the past 20 years the top go-to foods when people needed a quick energy lift have been cakes, cookies, breads, pastries, bags of salty snacks, and cups of sugary beverages. I live down the street from the DePaul University student union, cafeteria, and snack bar. With the food choices available, students are lucky if they escape with only the Freshman 15.
Recommendations based on the CIM model
According to CIM researchers, here’s a summary of how Susan should eat:
–Reduce refined grains, potato products, and added sugars including high-glycemic load (GL) carbohydrates with low overall nutritional quality.
–Emphasize low-GL carbohydrates, including non-starchy vegetables, legumes, and non-tropical whole fruits.
–When consuming grain products, choose whole kernel or traditionally processed alternatives (e.g., whole barley, quinoa, traditionally fermented sourdough made from stone ground flour).
–Increase nuts, seeds, avocado, olive oil, and other healthful high-fat foods.
–Maintain an adequate, but not high, intake of protein, including from plant sources.
–For individuals with severe insulin resistance, metabolic syndrome, or type 2 diabetes, restriction of total carbohydrate intake, and replacement with dietary fat, may provide greatest benefit.
If you need some help with this model of healthful eating and effective weight loss, schedule with Marla Feingold or Olivia Wagner. Also, familiarize yourself with a glycemic index website such as this one. Take a look, too, at this visual presentation of carbs in vegetables and this one on fruits.
David Edelberg, MD