I had been planning to post this in early January 2020, when New Year’s resolutions were on everyone’s minds, but as it often does, life got in the way, and now here we are…January is fading into February, and chances are, so is your resolution to stick with your resolution. This is precisely why I have no use for New Year’s resolutions, because I figure if something is that important, I should be sticking to it throughout the year, not just for a couple of months (or weeks, or days..) while I am pumped up for the New year!
But for those of us who really need to shed those ever so annoying pounds that surreptitiously snuck up during the holiday revelry, (ahem, ahem-that includes yours truly), here’s a word of advice if I may…
Ditch the diet mentality!
And start living! Let go of the self-imposed shackles of endless dieting, and embrace eating the way we were meant to eat. Real food, whole and wholesome. Nothing fake, nothing extreme. Nothing unsustainable. In particular, I would like to unabashedly bring to light some of the most popular diets out there that appear to be so fixated on driving all carbs out of circulation as it were, and making either proteins or fats (or both), center stage. While we all need all 3 macro-nutrients, which would include the said proteins and fats, when the scale begins to tip (exclusively or near exclusively) and sometimes dangerously, in favor of animal sources of fat and protein to the exclusion of healthy* carbs, putting the health of gullible consumers at risk, the Registered Dietitian in me feels compelled to say something:
Science or pseudoscience?
Let’s start with investigating the science behind these diets, shall we? What are the commonalities between some of the low carb, high protein (Atkins, Paleo**) diets or low carb, high fat diets such as keto?
The relatively healthy versions of these diets encourage avoidance of sugar and refined carbs, and most all processed foods (thumbs up of course, that’s a no-brainer; you did not need me to confirm that!). And just in case you’ve been eating shall we say, unadulterated junk prior to embarking on these regimens, of course you are going to lose weight when you switch to the said diets and a whole, beneficial cascade effect is almost guaranteed to follow as noted here, such as lower blood sugars in diabetic individuals, lower blood pressure, improved cholesterol…and yes, quite likely, improved inflammatory markers as well. Thus, arguably the short-term benefits are there. So, what’s the problem?
For starters, when you eliminate whole grains and legumes, sometimes fruit as well, you just eliminated a vital component in your diet called fiber. Not to mention, essential minerals and vitamins. Sorry to say that while carbs currently have earned the dubious distinction of the “ugly step children”as it were, fats elevated to stardom (thanks to keto), and proteins considered the food equivalents of “American Idol”, (thanks to practically every diet in recent times from Atkins, to Paleo to Whole 30…), fiber, it turns out is the dark horse in our diets that has simply not received the attention that it so rightly deserves. The common denominator in most of these “diets” is the avoidance or elimination of healthful, high fiber carbs such as whole grains and legumes. (By the way, since when did legumes become inflammatory, as postulated by The Whole 30??).
Collateral damage: Loss of fiber from the loss of carbs!
The sad demonization of all carbs by our popular culture has led to some collateral damage. How so? Fiber only comes from carbohydrates, so when low carb dieters eliminate healthful carbs, unbeknownst to some, if not most of them, they end up tossing out the fiber too, which is self-defeating.
Let’s look at the premise upon which some of the high protein (Atkins/Paleo) or moderate protein/high fat diets such as keto are predicated upon:
The Carbohydrate Insulin Model of obesity (CIM )
As we increase our intake of carbs, the subsequent glucose spike causes a proportionately large amount of a hormone called insulin to rush out of the pancreas to offset the rise in glucose or sugar. Since insulin happens to be a fat storage hormone, large circulating levels of insulin in the body may inevitably lead to weight gain. Think of insulin as a prison warden, marching up and down the corridors, barking out orders, “lock up those prisoners and do not let them out”. Thus, the CIM of obesity postulates that a high carb diet causes the body to lock fat up for good, preventing access to, and mobilization of these fat stores. The decreased availability of fat as fuel for metabolically active tissues is perceived as a state of internal starvation leading to a compensatory decrease in calories burnt, and increased hunger and food intake.
Taking a cue from the CIM above, if we reduce our carb intake, replacing it with an equivalent amount of fat or protein, the decreased insulin levels will then allow access to the body’s fat stores and subsequent weight loss. However, does this theory hold water? Not so fast, according to the following studies:
The Case against low carb diets
The Dietfits study
In this 12 month, randomized clinical trial called the Dietfits trial published in the Journal of the American Medical Association or JAMA, they randomized 609 generally healthy, overweight or obese adults without diabetes to either a healthy, whole foods, low fat diet, or a healthy, low carb diet and there was no significant difference in weight loss between the 2 groups as long as the diets were in isocaloric amounts (i.e., they had the same amount of calories, so the investigators in these studies were making a fair comparison).
The ARIC study
Then there was the ARIC (Atherosclerosis Risk in Communities study), a large, long term prospective study with a medium follow-up of 25 years, which looked at how the percentage of carbs in your diet affected mortality risk. What was interesting about this study was that a U-shaped curve was seen. The study showed that when carb intake went below 40%, the mortality risk went up. However, the mortality risk also went up when the carb intake exceeded 70%, creating the aforementioned U-shaped curve with the sweet spot around 50-55% carb intake.
Most people do not just give up carbs. They have to replace those carbs with something else, or else they would starve. So the question that arises is: I decreased my carb intake-but which macro-nutrient am I replacing my carbs with? Turns out that when those carbs are replaced with animal protein, mortality goes up, when they are replaced with plant proteins, mortality goes down. Low carb dietary patterns favoring plant derived protein and fats such as nuts, nut butters, vegetables and whole grains were associated with lower mortality. According to the authors of this study, this data provides “further evidence that animal-based low carbohydrate diets, which are more prevalent in North American and European populations, should be discouraged”.
Gut bacteria: Calling the shots??
Furthermore, some of the most compelling research in favor of healthy carbs also comes from the little critters in our gut, our gut bacteria. Turns out that these little, invisible organisms are calling the shots when it comes to chronic disease.
Emerging evidence shows that high fat diets in both human beings as well as in mice have been shown to create a conspicuous absence of the beneficial “Bifidobacteria”. Bifidobacteria play a key role in protecting gut barrier integrity and function, so as their numbers dwindle, this gut wall is compromised, leading to increased gut permeability and the so called “leaky gut”, which allows harmful bacteria to sneak through this leaky wall into your blood stream and trigger chronic, low grade inflammation, associated with metabolic disease states such as diabetes, heart disease, as well as obesity, to name a few.
So also, high protein, low carb, low fiber, weight loss diets in human beings may produce toxic substances that could be detrimental to the health of your colon as noted here.
In addition, beneficial bacteria encode enzymes that can degrade complex, indigestible polysaccharides (i.e. fiber), and ferment these fibers to produce organic acids that not only promote gut integrity and provide fuel to the cells in your colon, but the resulting acidic ph inhibits the growth of “bad bugs”. Clearly all these metabolic advantages are lost with a high fat diet as it is just not conducive to the growth of these beneficial bacteria. Moreover, friendly bacteria feed on fiber derived from carbs. When you feed something, it grows, thrives, and sticks around. When you starve those bugs, they have no incentive to hang on, and will bid you farewell. Which raises an important question-will fiber starved bacteria from a carb restricted diet lead to poor health? In addition, to nourish a healthy microbiome, we need a large and diverse variety of whole plant foods from fresh fruits, veggies, whole grains, and legumes. The limited veggies and spattering of fruit (30-50 grams or less in some cases, with the keto or an Atkins-like diet) may not cut it, thus having a deleterious effect on the gut microbiome, driving out beneficial bacteria and setting the stage for “dysbiosis” (an imbalance between good and bad bacteria), and possibly subsequent inflammation. That said, more human clinical trials are needed to draw any firm conclusions, but the research so far is compelling.
Easy come, easy go?
I’m sure what many of you might find most appealing about low carb diets is the rapid weight loss induced in the first week or so. If you think you are burning fat at the get go, think again. Typically, a 500 calorie deficit (the difference between calories consumed and calories needed to support your current weight), results in a 1-2 lb weight loss per week at best. (500 x 7 = 3500 calories = 1 pound lost). The low carb diet might produce a 5 pound or higher weight loss in week 1. Why, and how? Your body stores glucose in the form of a compound called glycogen. Well, when carbs are restricted, your body reacts by kicking off 2 processes. First off, it begins to burn its glycogen stores in order to fill the energy gap. For every gram of glycogen, you lose approximately 3 grams of water. Given that you have approximately 100 grams of glycogen in the liver and 400 grams in muscle, that’s roughly a kilogram and a half to approximately 2 kilograms of water loss. But glycogen stores last approximately 18-24 hours only, after starting a carb restricted diet, so the body must turn to an alternate fuel source, once those glycogen stores are depleted.
That alternate fuel source as you may have guessed, is fat and the breakdown of body and dietary fat when there is limited carbs available from a low carb diet, leads to the formation of ketones. This in turn causes sodium and water loss in the body adding to the total body water loss, often perceived as less bloating by the folks on these restricted carb diets. In addition, ketones have an appetite suppressing effect that can help low carb dieters. Unfortunately, much to their dismay, weight is regained once these folks start eating a regular diet again.
Nutrient scarcity, downright scary!
Excluding whole grains, legumes, fruits and including only small amounts of vegetables creates a new problem. A variety of nutrient deficiencies are seen as these diets tend to be low in calcium, magnesium, iron, Vitamin D and phosphorus, often requiring mandatory supplementation. In addition, the loss of sodium through diuresis (your body flushes out water as explained earlier), means you also have to supplement the diet with salt to prevent feeling light headed from a drop in your blood pressure. Although you could certainly supplement the diet with the missing nutrients, I would regard that as a huge red flag. A nutritionally adequate diet requires little, if any supplementation. Thus, if you have to supplement your diet regularly with an array of vitamins, minerals, and not to mention stool softeners (the lack of fiber from the lack of carbs might impact your ability to eliminate waste), that should serve as a red flag that something fishy is going on.
The low down on high protein diets
The repercussions of excess protein with some low carb diets would include excess burden on your kidneys to flush out the “waste” produced from protein, increasing the risk of dehydration, gout and kidney stones. One should note that the keto diet is not technically a “high protein” diet as roughly only 15-20% of its calories are derived from protein. Higher amounts would allow conversion of protein to glucose, and abort the very mechanism that creates ketosis***. That said, the dehydration from loss of body water puts keto followers, like other low carb followers, at an increased risk of kidney stones and gout unless they are expertly guided and monitored by their health care providers.
Does this mean there is no room whatsoever for a low carb diet ??
Let’s look at the evidence supporting a low carb diet.
The case for high protein/low carb diets:
In this randomized control trial that compared the effects of a very low-carbohydrate, high-unsaturated/low-saturated fat diet (LC) with those of a high-unrefined carbohydrate, low-fat diet (HC) on blood glucose levels and cardiovascular or heart disease (CVD) risk factors in type 2 diabetes patients, while both diets achieved substantial improvements for glucose levels and CVD risk markers, the improvements were greatest with the LC compared with HC.
A closer look at these diets shows that the saturated fat content was < 10% for both, that while the % of calories from fat in the LC was significantly higher (58% vs < 30% ), the source of fat was 35% of heart healthy MUFA ( mono-unsaturated fats), and 13% PUFA ( polyunsaturated fats), derived primarily from whole plant fats such as nuts and oils high in MUFAs. Most importantly, while the % carb intake in the LC diet was only 14% vs 53% in the HC diet, the total fiber intake was a relatively high 25 grams, (foods included high fiber cereal, non-starchy veggies and nuts), in sync with the US Dietary guidelines and only slightly lower than the HC diet with 31 grams of fiber/day. That said, this was only a 24-week trial, which leaves one wondering if the low carb lifestyle would be sustainable.
This issue was addressed in this study where long term weight loss and cardiometabolic effects of a very-low-carbohydrate, high-saturated-fat diet (LC) and a high-carbohydrate, low-fat diet (LF) were evaluated. Both diets had the same amount of calories. The LC diet was shown to have some clinical benefits in obese individuals with insulin resistance, however the LC diet also raised LDL or “lousy” cholesterol, a key marker of heart disease, and an important finding that cannot be overlooked in our quest to seek an optimal meal pattern.
Finally, let’s look at how the Mediterranean diet stacks up in comparison…
Mediterranean diet: A win-win?
A multi-center trial in Spain assigned 7447 participants who were at high cardiovascular (heart disease) risk, to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet (folks in this arm were advised to reduce dietary fat). The study showed that the incidence of major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet.
Thus a carefully designed low carb diet that is plant based, low in saturated fat, emphasizing unsaturated fats with good amounts of fiber through whole plant foods has been shown to be as effective, if not more than the HC in terms of a favorable impact on heart disease markers.
What’s the take-away?
The “source” of carbs and macros matters. Quality counts!! At the risk of stating the obvious, there is a huge difference between choosing a ciabatta roll or choosing farro as a carb source at lunch. Low carb and/or low fat in and of themselves means very little if we do not investigate where these macronutrients are coming from, something that the popular culture often ignores, much to the detriment of readers like you. Some of us are insulin resistant and might need a lower carb diet, but if you choose to incorporate low carb, the evidence favors a dietary pattern with plant derived protein and fats such as nuts, nut butters, vegetables and whole grains rather than animal fats and protein to get the best results. Alternatively, if restricting carbohydrate intake is a chosen approach for weight loss or for heart disease risk reduction, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to promote healthy ageing as noted by the authors of the ARIC study.
Sifting through the mountain of evidence so far, for optimal results that go beyond a narrow waistline, a Mediterranean style meal pattern appears to make the cut!
Translating the Mediterranean diet into everyday food choices
As an example, swap the bacon and eggs for high fiber oatmeal with walnuts for protein and whole plant-based omega-3s, add some black beans to the salad with chicken at lunch and throw some barley or farro into that chicken-vegetable soup at dinner. Eat nuts or an apple as a snack.
Look before you leap: Even if you choose to follow a low carb diet, understand the consequences, and make sure to include the carbs that give you the biggest bang for your buck i.e. nutrient dense, with the greatest amount of fiber per serving along with lean proteins and whole plant fats. Clearly all carbs are not created equal. Don’t turn your back on the wholesome, healthful, satiating, antioxidant-rich, and potentially anti-inflammatory, high fiber carbs as that would be akin to throwing out the baby with the bath water!
And guess what? If you mindfully follow such a Mediterranean style meal pattern, your body will thank you given that such a balanced diet would give your body what it needs, stopping food cravings. Along with this meal pattern if you stay reasonably active, you will not need to count any calories either because of the satiety effect of fiber, among other benefits. Who said you can’t have your apple and eat it too?
A lifestyle change that changes your life!
Finally, to end with the same point that I set forth in the beginning, break out of the relentless diet roller coaster. Practice mindfulness in all aspects of your life including mindful eating, mindfulness meditation and make a conscious attempt to stay active. Above all, embrace lifestyle changes that you can not only live with, but which allow you to thrive and promote a total sense of well being, where body, mind and spirit are aligned and in harmony!
Here’s to a very Happy and Healthy 2020!
*whole grains, fruits, legumes and vegetables.
**Paleo is a high protein diet that does not aim to be low carb (unlike Atkin’s and Keto), but by default it ends up becoming one, by throwing out the healthful whole grains, legumes and dairy, albeit while allowing its followers to eat fresh fruit.
*** When glycogen stores are depleted after ~ 24 hours on a low carb diet, the body has to fill the energy gap by oxidizing fats in the liver, leading to the production of ketones. If there is excess protein in your diet, some of this protein can be converted to glucose by the body for energy. As long as the body has glucose as a source of fuel, it is going to pounce on it given that glucose is the primary fuel source for the brain, and consequently the production of ketones will stop in its tracks.
Disclaimer: The material presented here is based upon the available research at this point in time. It is understood that there may be changes in the evidence that occur over time. This blog is strictly for informational purposes only and should not be construed as medical advice. Please consult your physician or registered dietitian for recommendations tailored to your specific needs.