I decided to dedicate my first entry this year to diets. Actually, when I was creating my website and my YouTube channel I primarily wanted to talk about dieting and the science behind weight loss and metabolic health but somehow I managed to focus on bits and pieces of science such as describing metabolism or macronutrients rather than on diets themselves – I've made a couple of blogs on diets already, but I am still far away from my original goal, so I decided to make 2020 the year of the diet! This blog will serve as an introduction to a long series of reviews and today I would like to talk about the very definition of the term "Diet" and to provide you with an overview of the diets I am planning to cover in this series.
As promised, the very first diet I am going to review in this series is the Standard American Diet also known as the Western Diet or the Western Pattern Diet. I like the former name as it abbreviates as SAD and in my opinion reflects the quality of this diet quite accurately. On a more serious note – these terms (and diets) are interchangeable as the Standard American Diet is effectively a localized version of the Western Diet – they have the same origins and very similar sources of nutrients. I say similar because there is always some variation in the diet composition depending on the specific country or area where the food is being produced and consumed.
One important thing I would like to mention is that since it’s a naturally occurring diet there is really no good definition or scientific description for it, again, due to local variation of the food sources, cultural elements and nutritional patterns. There also seems to be a noticeable change in this nutritional pattern over time1. Accordingly, there is not too much research that would directly refer to either of these diets, which is actually quite shocking – with all the wealth of nutritional research to date there are only 3 publications with Standard American Diet in the title on PubMed and 388 – on the Western Diet. Still, there are some good publications that we can refer to (see Kopp 2019, Grotto et al 2010, Cordain et al 2005). 1-3
The Origins of the Western Diet
The main reason why I wanted to talk about this diet to begin with and about its origins specifically is that this diet reflects the history of our civilization and the evolution of our contemporary eating habits. Approximately 10,000 years ago the agriculture and animal husbandry emerged and they changed the way we acquired our food – instead of relying on hunting, fishing and gathering, which often gave us very poor yields, relied heavily on our physical prowess and required a lot of intense physical activity, we turned to a gradual development of steady, predictable, and eventually – very cost-effective sources of nutrition. Don’t get me wrong – farming still required a lot of physical effort, but it was a different kind of activity, which we could split between different members of our communities and the average yield was way higher than in the case of hunting-gathering. Over the course of the millennia of hard work, we acquired, cultivated and domesticated new species of plants and animals, developed progressive techniques of breeding and farming, which led to introduction of some foods that we were not accustomed to before, such as potatoes for example, which were not available in Europe prior to the discovery of Americas. We learned how to process foods differently and acquired access to new foods, such as alcohol, cereals or bread for example. We learned how to store, to preserve and to transport them effectively and now we have access to pretty much anything all year round. And finally, with the industrialisation we reached such a level of cost-effectiveness that the price of nutrients became very low – we can have lots of nutrients for a small fraction of our budget at any time of the day and the year.
The Nutrient Composition of the Western Diet
The nutrient composition of the Western Diet varies with the region and its cultural peculiarities. Notably, again, since it’s such a diverse family of diets I was not able to find a good normative data for the Western Diet – even the few epidemiological studies that I was able to find, described the nutritional patterns of the whole population, which included a decent number of people who were not on the Western Diet. In any case, knowing the origin of the diet and the bits of research data we do have, we can try to describe this nutritional pattern.
First, since there a true cornucopia of foods this diet is characterized by consumption of a large quantities of foods, typically well in excess of the recommended caloric norms. The food comes from a variety of sources – both animal- and plant-based. There is also a tendency of snacking, which leads to high frequency of food intake as well as the heavy reliance of restaurant and prepackaged foods, so the portions tend to be large and there is a number of stabilizing agents and preservatives in the foods we consume i.e. there are lots of processed foods in this diet.
In terms of specific food groups and macronutrient intake, the Western Diet is characterized by consumption of substantial amounts of foods that were virtually not available or available in much smaller quantities 10,000+ years ago such as grains, refined and added sugars, milk and dairy products and a higher variety of fats, including increased amounts of animal fats (wild animals tend to be much leaner than their domesticated counterparts), refined vegetable oils, solid oils etc. Another important item on our food list if alcohol, which became a very important element of our nutritional pattern.
Finally, the distribution of three major macronutrients is as follows: an average American consumes 265 g of carbohydrates (50% of daily caloric intake), 78.3 g of fat (33%), and 78.1 g of protein (15%). Surprisingly, these macros are consistent with the existing dietary guidelines. Even the average cholesterol consumption of 276 mg per day was within the recommended daily amount of 300 mg or less. I must say, that there is either something missing in the picture here i.e., something is wrong with the research data, or something is wrong with the guidelines since the diet that is considered to be the source of all our health issues seems to fit them so well, but I will address this discrepancy in my future blogs. Finally, the consumption of fiber and potassium is half of the recommended amounts and the intake of sodium exceeds the recommended amount by 49%2.
Health effects
The Western Diet was implicated in multiple health issues called collectively the diseases of civilization3. Based on what I have learned over the decades of health research, I tend to agree with this statement, but with a little twist – my understanding of the health effects of the Western diet and the ideas behind the Western nutritional guidelines are quite different. Again, I will talk about the guidelines later in the series. Now, I see at least two major problems with the Western diet: first, we consume too much food – it’s easily available and we are in a constant caloric surplus, which leads to weight gain and eventually – to obesity and related health issues. The second problem is consumption of foods that we are not genetically fit to eat in such quantities – primarily the foods that have lots of carbohydrates in them, especially refined ones (sugar, honey, corn syrup, corn and potatoes, bakery). In addition to that, high frequency of food intake, consumption of unnatural kinds of fats, stress and inactivity lead to profound changes in our metabolism, which in turn lead to atherosclerosis, type 2 diabetes, cardiovascular diseases and many other health problems3. There is an emerging evidence of associations between the Western diet and changes in gut microbiome4, inflammation5 and autoimmune disease6, neoplasms / cancer, cognitive issues and dementia risk7,8, which also deserve separate entries in this series.
Is it a good or a bad diet?
Despite all the negativity around this diet, it is the nutritional pattern that emerged with our civilization and effectively reflects our evolution as a species. It allowed us to survive and to thrive for millennia – at the moment, we have the highest population ever, we have the longest lifespan ever and we can have all kinds of foods without working hard for them. On the other hand, there are indeed multiple issues that need discussion and research, specifically the effects of the diet, not just the Western diet – any diet, and specific nutrients on our health, performance and longevity, which is ultimately the focus of this series. I will be covering all these items in my future blogs. Today we have laid down the foundation for the discussion of other nutritional patterns and recommendations, such as dietary guidelines, pre-agricultural nutritional patterns (Paleo diet), low-calorie, low-carbohydrate, low-fat diets etc. I hope it will be interesting and educational and if you don’t want to miss anything, please subscribe to my website and to my YouTube channel – there is a lot of information presented there. And of course, you can always ask questions, make your comments and suggestions either on YouTube, or here on my website.
Sincerely Yours,
Dr.Sam
Video: Diet Review Series: The Standard American / Western Diet
References:
1. Cordain L, Eaton SB, Sebastian A, et al. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr. 2005;81(2):341-354.
2. Grotto D, Zied E. The Standard American Diet and its relationship to the health status of Americans. Nutr Clin Pract. 2010;25(6):603-612.
3. Kopp W. How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases. Diabetes Metab Syndr Obes. 2019;12:2221-2236.
4. Statovci D, Aguilera M, MacSharry J, Melgar S. The Impact of Western Diet and Nutrients on the Microbiota and Immune Response at Mucosal Interfaces. Front Immunol. 2017;8:838.
5. Christ A, Lauterbach M, Latz E. Western Diet and the Immune System: An Inflammatory Connection. Immunity. 2019;51(5):794-811.
6. Manzel A, Muller DN, Hafler DA, Erdman SE, Linker RA, Kleinewietfeld M. Role of "Western diet" in inflammatory autoimmune diseases. Curr Allergy Asthma Rep. 2014;14(1):404.
7. Noble EE, Hsu TM, Kanoski SE. Gut to Brain Dysbiosis: Mechanisms Linking Western Diet Consumption, the Microbiome, and Cognitive Impairment. Front Behav Neurosci. 2017;11:9.
8. Shakersain B, Santoni G, Larsson SC, et al. Prudent diet may attenuate the adverse effects of Western diet on cognitive decline. Alzheimers Dement. 2016;12(2):100-109.