A Foundation for Health: Feast Versus Famine: It is a common misconception to think we have evolved in a way that is superior to our past. After all, most of us live in an environment where anything we want is at our fingertips. But is this always a good thing?

Evolutionary medicine is research that looks at biological changes that have occurred in humans over time and how these changes may affect our health. Many of these adaptations are clearly beneficial – such as the growth of our brain size¹  Still, with development and progress, we have also increased our vulnerability to diseases such as obesity² And given over 40% of the US population is obese. even though the diet industry is worth $72 billion⁴ we are clearly out of touch with what our bodies need. We now know that the mantra “calories in equals calories out” for weight loss isn’t true. Otherwise, weight-loss diets based on caloric restriction wouldn’t fail all the time.

Instead, we should focus on looking back at what the body was designed to do and how to use biology to our advantage efficiently. An eating pattern known as “feast versus famine” that naturally existed in our past due to changing food accessibility can be applied to modern lifestyles to benefit our health.

What is feast versus famine?

Our ancestors lived in a different environment than the current immediate gratification world. With changing seasons and climates, hunter-gatherers would adapt their diet based on food availability. Fasting was necessary when food was scarce. At other times more carbohydrate-dense foods were abundant, and starchy roots, tubers, and berries would increase in their diet. And when meat, fish, or game was available, the diet resembled a ketogenic pattern.

This food availability began a cycle of hormonal and metabolic adaptations that unknowingly set our ancestors up to benefit their health. As we now know, during fasting and ketosis, the body focuses on healing and repair through autophagy. When entering into temporary times of “feasting” with an increased intake of starchy carbohydrates, they were able to disrupt the metabolic stress hormones that signal the risk of starvation while promoting stem cell growth.⁵

How does feast versus famine compare to modern-day eating patterns?

While several small populations of hunter-gatherers follow a similar lifestyle,⁶  most of us have access to food whenever we want it. And this is precisely the problem. Diet culture bounces people from diet to diet, promising the best results. A person may feel better for a while but soon lose their way, either gaining the weight back or feeling worse than before starting.

The average person not only eats too much but too often. While the cyclical ancestral patterns allowed for periods of famine in-between times of feasting, we are in a constant “feast” state. This state includes how much we eat, how often, and what we eat. Even many “diets” allow – or encourage – eating meals and snacks all day. The body never gets a break; insulin continually spikes, leaving us in constant inflammation.

Many people are also so removed from hunger cues that they don’t even know how to eat. Many people are pre-programmed to see 12:00 on the clock and think “lunchtime” regardless of whether they are hungry.⁷ The three meals a day with snacks in between pattern is a creation of modern lifestyle and does not match up to biological adaptations in which our body thrives.

In fact, studies have shown that over time some humans express genes that allow them to hang onto extra fat in case of times of famine. Known as the “thrifty genotype,” this theory tells us that certain people may convert excess calories to fat to save for fasting times to survive^.8 These people will hold onto stored fat more easily than others, risking their health given they don’t experience the famine as was biologically predicted.

When we don’t eat according to our natural biology, we risk overriding fundamental signaling mechanisms, such as circadian rhythms.⁹  Most of us are familiar with the role the circadian rhythms play in regulating sleep in the body, but they do much more than signal the body to go to sleep. Cells that play a role in immune and metabolic health also respond to cues from our circadian rhythms.¹⁰ Overriding these innate signaling molecules can disrupt processes in the body that help with energy balance and even increase our risk of chronic disease.¹¹

How can we apply the feast versus famine concept to modern life?

While we can’t go back to the ancestral lifestyle (and probably don’t want to), we can carry some of the principles to our diet patterns to benefit our health. The patterns of feast versus famine, while eating seasonal, fresh foods, can impact our health significantly if we apply them correctly.

We can use these concepts in the modern-day by cycling through several ways of eating, or what we call diet variation, by combining three principles:

• Intermittent fasting.
• Ketogenic diet principles.
• Feasting on appropriate food choices.

While the benefits of each of these concepts require their own article, let’s examine each a bit closer:

1. Fasting: Intermittent fasting mimics periods of famine in indigenous lifestyles. Using fasting principles, we can apply the periods our ancestors went without food. We know the benefits of fasting are numerous – from longevity to weight loss to blood sugar control and more. Fasting addresses eating less often instead of eating less. The typical “calories in equal calories out” weight loss diet fails as the body adapts and reaches plateaus.¹² By taking structured periods of fasting, we allow our body to take advantage of the innate, biological adaptations developed through evolution.

2. Ketogenic diet: As described, our ancestors would experience seasonal shifts where plants may have been scarce, so meat and game were the only options for food. We can mimic this pattern initially used as a survival mechanism to live with limited food options with a nutrient-rich ketogenic diet to obtain the same health benefits, including autophagy, as seen with fasting.¹³

3. Feasting: Still focusing on nutrient-dense foods, but allowing the body to cycle out of keto to reduce stress on the body, further supports hormone adaptations. While we know that the ketogenic diet has impressive benefits, it may not be necessary, and even detrimental for some, to follow it strictly all the time. Instead, we can plan for a period of feasting when we open up our diet to include more berries and starch-based plants so the body doesn’t believe it is in danger of starving.

By following these three patterns, we not only consider our biology but also address other issues with diet changes – including feelings of deprivation and boredom, which can ultimately interfere with the best intentions of diet changes.

Considering feast versus famine when making diet changes is an under-utilized tool to wake the body up to its intrinsic patterns. If you are someone who has struggled when following only one diet or aren’t seeing desired results – this is the next crucial step to optimizing your health.

References:

1. Neubauer, Simon, Jean-Jacques Hublin, and Philipp Gunz. “The Evolution of Modern Human Brain Shape.” Science Advances 4, no. 1 (January 1, 2018): eaao5961. https://doi.org/10.1126/sciadv.aao5961.
2. Grunspan, Daniel Z et al. “Core principles of evolutionary medicine: A Delphi study.” Evolution, medicine, and public health vol. 2018,1 13-23. 26 Dec. 2017, doi:10.1093/emph/eox025
3. “Products – Data Briefs – Number 360 – February 2020,” February 28, 2020. https://www.cdc.gov/nchs/products/databriefs/db360.htm.
4. Markets, Research and. “United States Weight Loss & Diet Control Market Report 2019: 2018 Results & 2019-2023 Forecasts – Top Competitors Ranking with 30-Year Revenue Analysis.” Accessed May 23, 2020. https://www.prnewswire.com/news-releases/united-states-weight-loss–diet-control-market-report-2019-2018-results–2019-2023-forecasts—top-competitors-ranking-with-30-year-revenue-analysis-300803186.html.
5. Kanchan P., Scarth W. A., Katharina S. A. Tightrope act: autophagy in stem cell renewal, differentiation, proliferation, and aging. Cellular and Molecular Life Sciences. 2013;70(1):89–103. doi: 10.1007/s00018-012-1032-3.
6. Gibbons, Ann, and Matthieu Paley. “The Evolution of Diet.” National Geographic, www.nationalgeographic.com/foodfeatures/evolution-of-diet/.
7. Bingeman, RDN, CD, Brittany, and Jaqueline Neid-Avila, RDN, CD. “Learning to Listen to Hunger and Fullness Cues.” Utah Extension, digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2851&context=extension_curall.
8. Michael J. Wargovich, Joan E. Cunningham, Diet, Individual Responsiveness and Cancer Prevention, The Journal of Nutrition, Volume 133, Issue 7, July 2003, Pages 2400S–2403S, https://doi.org/10.1093/jn/133.7.2400S
9. “How Eating Feeds into the Body Clock.” ScienceDaily, ScienceDaily, 25 Apr. 2019, www.sciencedaily.com/releases/2019/04/190425143607.htm.
10. ^[10] Zarrinpar, Amir et al. “Daily Eating Patterns and Their Impact on Health and Disease.” Trends in endocrinology and metabolism: TEM vol. 27,2 (2016): 69-83. doi:10.1016/j.tem.2015.11.007
11. ^[11] Patterson, Ruth E, and Dorothy D Sears. “Metabolic Effects of Intermittent Fasting.” Annual review of nutrition vol. 37 (2017): 371-393. doi:10.1146/annurev-nutr-071816-064634
12. [12] Hall, K.D. (2018), Metabolic Adaptations to Weight Loss. Obesity, 26: 790-791. doi:10.1002/oby.22189
13. ^[13] Bose, K S, and R H Sarma. “Delineation of the intimate details of the backbone conformation of pyridine nucleotide coenzymes in aqueous solution.” Biochemical and biophysical research communications vol. 66,4 (1975): 1173-9. doi:10.1016/0006-291x(75)90482-9