Seasonal Oscillation of Sugar, Starch, Saturated Fat, Polyunsaturated Fat & Monounsaturated Fat

Ever wondered why different diet camps are down on different components of our diet?

  • The low-fat crowd seems to hate saturated fat and cholesterol. 
  • Meanwhile, keto and low-carb enthusiasts fear sugar.
  • More recently, many have become convinced that polyunsaturated fat is the culprit for the diabesity epidemic.

But as you will learn in this article, each of these ‘bad’ sources of energy in our diet ebb and flow in a natural rhythm with the seasons. 

Each energy source is fine in its whole food form, safely contained in the nutrient-dense package that Mother Nature lovingly prepared for us.  Whole foods give us a dopamine hit, ensuring we enjoy it and remember to eat so we don’t starve.   

Our data shows that we tend to eat a lot more when we transition from winter to summer and back from summer to winter.  These special times are marked by feasting festivals that date back thousands of years. 

But modern food engineering has perfected the art of combining multiple energy sources in the right amounts to hit our bliss points 24/7/365.  This creates a constant supra-physiological dopamine response, making us buy and eat more than we need from these engineered ultra-processed foods.

Big Food companies profit from the demise of our health, and drug companies ‘rescue’ us with injections of artificial satiety to quiet the food noise created by ultra-processed foods.

To help you navigate our modern food environment, this article will:

  • Explain why ultra-processed foods’ unnatural combination of energy sources is so addictive.
  • Empower you to make more intelligent food choices, focusing on seasonal nutrition and natural food rhythms.

Curious to learn more?  Read on.

Highlights: The Circannual Cycle of Fats and Carbs

Our analysis of 155676 days of data from our Optimisers shows that, even in our modern food environment, each energy source oscillates with the changing seasons.  In days gone by before food processing, transport and refrigeration, these swings would have been much larger. 

If we double-click on the carbohydrates, we see that energy from sugar peaks in summer and declines in winter, while starch has a lower and later peak and declines in late autumn. 

Meanwhile, when we double-click on fat, we see that monounsaturated fat supplies more energy in winter.  In contrast, saturated fat rises more in autumn.  Increased energy from fat is the major contributor to extra energy intake during the onslaught of feasting at the end of the year.  

When we overlay all the energy sources together, we see that when overall energy intake is lowest, there is more separation between the energy sources.  We eat less when our energy comes mainly from either carbs or fat. 

But it’s the danger zone between summer and winter that gets us into trouble. When the energy sources combine, they create the perfect blend that drives us wild! 

To leverage the circannual nutrition insights, we can:

  • Prioritise fresh, whole, seasonal foods that will naturally cycle with the seasons. 
  • Enjoy a lower-carb or lower-fat diet, both of which avoid the intersection of all the energy sources.   
  • Prioritise protein-rich foods, which contain less energy from both carbs and fat. 
  • Avoid low-satiety ultra-processed foods that provide the magical blend of energy sources that rarely occur in nature. 

To dive into the details, read on. 

The Seasonal Dance of Carbs and Fats

In our previous article, we examined how macronutrients—protein, fat, and carbohydrates—vary with the seasons. The data shows that we eat a lot less and lean out when our energy comes mainly from one source, either fat or carbohydrates. 

Rather than fat or carbs being necessarily ‘bad’, the ‘problem’ with our modern food environment appears to be the fact that ultra-processed foods mimic the magical fat and carb combo foods that are rare in nature other than:

  • Spring – when we need to regain some body fat after winter, and
  • Autumn – when we need to gain fat to survive the coming winter. 

To recap, the chart below shows the fluctuations in carbs and fat in 155,676 days of food logging from 16,661 Optimisers.  I’ve used a 13-week moving average to capture the longer-term swings in energy from fat and carbs across the year. 

As you can see, carbs tend to increase in summer, while fat takes a back seat.  But as we transition from summer into autumn, energy from fat and carbs come together in similar quantities, which aligns with eating more. 

Seasonal Energy Peaks

The chart below shows the variation in total energy intake across the seasons. 

Notice how energy intake drops in winter as the gap between carbs and fat widens.  We see another drop in summer as the gap between fat and carbs widens even more.  But in autumn, carbs and fat come together again, and we eat more. 

At first glance, it may seem that the chocolate at Easter and the slew of celebrations towards the end of the year may be the root cause of our dietary demise.  But, as discussed in the previous article, these modern feasting festivals have their origins in the harvest seasons from long ago.  

The Carbohydrate Chronicles: Seasonal Variations Unveiled

First, let’s explore the oscillation of the two major subsets of carbohydrates, sugar and starch.  Understanding these seasonal variations in food intake helps us align our diets with natural food rhythms and seasonal nutrition.

Sweet Insights: The Role of Sugar Throughout the Year

Sugar is a nutrient that gets a lot of bad press, particularly in lower carb and keto circles.  However, our data shows that, in line with food industry research, we have a distinct bliss point for sugar at around 18% of total energy.

We love the taste of sugar, but if we add too much, it can quickly taste ‘sickly sweet’, and we don’t want to eat as much of it.   You’ve probably never sat down to binge on a whole bowl of sugar.  Fruitarians, who consume a lot of sugar from fruit, are often skinny, to the point of being malnourished

If you’re on a very low-carb diet, it’s much easier to be seduced by high-sugar foods.  But if most of your diet is fruit, fat will be much more attractive than sugar. 

We prefer the Goldilocks zone between the extremes.  The low-satiety foods that most people can’t stop eating contain the perfect blend of each type of fat (saturated fat, monounsaturated fat and polyunsaturated fat) and carbohydrate (sugar and starch). 

When we look at the seasonal variation in sugar, we see a distinct peak in summer, likely due to higher fruit availability.  Between the lows of winter and the highs of summer, there’s a significant 18% drift in sugar as a percentage of our overall calorie intake.  These seasonal swings would have been much more prominent before modern food storage, preservative and processing technology. 

In each of the seasonal charts below, the total energy intake is shown as a grey line to help you see how the different nutrients align with overall energy intake across the year. 

Fascinatingly, although sugar is often considered a ‘bad’ nutrient to be avoided, peak sugar intake coincides closely with the lower energy intake during the summer.  

Peaking at 8.1%, our Optimisers don’t consume much sugar.  By comparison, the average American got around 18% of their total calories from sugar back in 1999, which happens to align with the bliss point sugar intake shown in our data and identified by testing by food companies.    But, sugar intake in the US has declined to around 13% since the introduction of artificial sweeteners

As shown in the infographics below, many fruits and vegetables have a relatively high satiety score despite their high sugar content.  Absolute sugar intake (in grams) correlates with eating more (R2 = +17%).  However, swapping fat for fruits and vegetables that contain more sugar aligns with eating less (R2 = -20%).

Take away:  Adding refined sugar aligns with eating more, but foods that naturally contain sugar, like vegetables and fruit, help us eat less because they displace other lower-satiety, energy-dense foods. 

Starchy Secrets: How Seasons Influence Starch Intake

While sugar is more abundant in fruits and non-starchy vegetables, starch is abundant in root vegetables and grains.  There’s quite a significant swing in starch intake across the year in percentage and absolute terms (27% and 25%, respectively). 

Like sugar, starch is high during summer when we eat less.  But our higher starch intake also overlaps with the spring and autumn feasts, contributing to the extra energy consumption.  While plain potato or flour is hard to overeat, the real problem comes when we add oil and make chips and pizza. 

Increasing the proportion of energy from starch, which displaces other foods, has a small positive correlation with energy intake (R2 = 12%).  However, adding starch to your diet substantially impacts overall energy intake (R2 = 35%). 

Takeaway: Starchy foods align with eating more.  Limiting starchy carbs reduces overall energy intake. 

Fat Facts: Understanding the Controversy

In the 1960s, the official narrative was to eat less fat.  Food manufacturers responded by creating low-fat products packed with sugar.  Then, in the 70s, Atkins pointed out that sugar spikes glucose and insulin (in the short term) and the low carb took off. 

Fortunately for the food industry, Splenda was approved in 1999, followed by a slew of other artificial sweeteners.  Big Food could now give the public what they wanted while keeping profits and taste high. 

As you can see from the rapid increase in ‘salad and cooking oils’ in the chart below, processed food manufacturers swapped high fructose corn syrup for artificially sweetened seed oils, which are cheaper and more efficiently absorbed. 

To make way for this explosion of refined seed oils, the official narrative subsequently switched to fat being OK as long as you kept your cholesterol low. 

Then, in 2005, after they realised that dietary cholesterol consumption doesn’t cause heart disease, the narrative transition to fat was OK, so long as it was the ‘good’ (unsaturated) fat and not the ‘bad’ saturated fat.   

Since then, monounsaturated fat from seed oils, which are incredibly cheap, have a high-profit margin and near-infinite shelf life, have become the mainstay of ultra-processed foods.

The Saturated Fat Story: Peaks and Troughs

While most foods contain a blend of each type of fat, saturated fat is the dominant fat in meat and dairy, which happens to be more expensive to produce and requires refrigeration, so it is less attractive as an ingredient in processed foods. 

Saturated fat makes up 18.6% of Optimisers’ overall energy intake.  Even in our modern times, we still see a distinct swing in saturated fat intake, with a low in summer, rising to a higher intake in autumn that coincides with maximum overall energy intake. 

Eating more saturated fat, which is a significant energy source, aligns with eating more, both in percentage terms and absolute quantities (R2 = 27% and 80%, respectively).

Monounsaturated Fat: A Seasonal Perspective

As shown in the chart below, created from data from the USDA Economic Research Service, monounsaturated and polyunsaturated fat have increased significantly over the past century, while saturated fat has risen only slightly. 

Although it trails saturated fat, we see an even more pronounced V-shaped oscillation in monounsaturated fat intake across the year.  While Optimisers’ intake of both fat sources bottoms out in early summer, we see more monounsaturated fat in winter and less in autumn than saturated fat. 

Compared to saturated fat, we see less of a correlation between monounsaturated fat and energy intake in both percentage and absolute terms (R2 = 7% and 50%, respectively).   

Polyunsaturated Fat: The Winter Peak Explained

It’s fascinating to note the offset peaks and troughs in our intake of the various fats across the year.  Each type of fat moves in offset cycles, peaking at different times of the year. 

Saturated fat intake peaks in mid-autumn, and monounsaturated fat peaks in mid-winter; meanwhile, polyunsaturated fat peaks a little later in winter and has a low intake at the start of autumn. 

Because these various fats are found in higher concentrations in different foods, we always get an oscillating blend of fat sources, at least from fresh, seasonal whole foods.  This oscillation would have been even more pronounced before the creation of ultra-processed foods, preservatives and refrigeration technology. 

Interestingly, the peaks in polyunsaturated fat don’t align with the peaks in energy intake across the seasons.  Adding more PUFA to your diet does increase energy intake (R2 = 24%).  However, if it displaces other energy sources, an increase in PUFA aligns with a reduction in energy intake (R2 = -20%). 

But because it’s the new fat on the block, PUFA and vegetable oils often get a bad rap.  However, of the three major fat types, it’s the only one that aligns with eating less (in percentage terms, at least)!  

While eating a ton of ultra-processed foods that provide most of their energy from artificially coloured and flavoured seed oils is definitely not optimal, you don’t need to avoid walnuts and seafood that naturally contain PUFAs. 

Our satiety analysis of a broader dataset shows that a higher percentage of any of the fats aligns with eating more.  But because it’s the dominant fat in our modern diet, increasing monounsaturated fat aligns with the most significant increase in energy consumption, with PUFAs only having a negligible impact.   

So, Which Fat is Best vs Worst? 

It seems that any of these fat sources in whole foods aren’t a big deal. 

However, modern processed food combines all of these energy sources in the perfect ratios to create the ultimate hyperpalatable food that makes us crave and eat the most.   It’s not that one fat is better or worse than the other. 

Instead, the problem comes when we combine them in a way that rarely occurs in natural food, which creates a supra-additive dopamine response that makes us feel ‘addicted’ to these foods. 

Fascinatingly, cholesterol follows a different trajectory from the other fats, peaking in early winter and bottoming out in spring and summer. 

Adding more cholesterol to your diet aligns with eating more (R2 = 37%), but eating foods with a higher cholesterol concentration aligns with eating less (R2 = -14%). 

Maybe dietary cholesterol is not bad after all despite being demonised for so long? 

Again, we see a clear bliss point for cholesterol.  Processed foods that contain a blend of cholesterol, starch and sugar (like the scones and brownie shown below) aren’t so great.  However, foods with the highest concentration, like oysters, salmon, and mackerel, are highly nutritious and satisfying. 

Omega 3: Seasonal Availability and Benefits

Our omega-3 intake is the highest from early summer to mid-autumn when seafood is plentiful.  However, because it only contributes a little to our energy intake, it doesn’t have a strong correlation with satiety or overall energy intake.   

Omega 6: Essential Nutrient with a Seasonal Twist

Our omega-6 intake is consistent throughout the year, with only a 3.4% variation from the peak in early summer to the trough in early autumn. 

Tight regulation of omega-6 makes sense, given that it is an essential nutrient the body can’t make from other substrates.  Similar to the other fats, a higher % omega 6 in your diet has a weak positive correlation with how much we eat. 

Balancing Act: The Omega 6:3 Ratio Throughout the Year

To round out the fat discussion, let’s look briefly at the omega 6:3 ratio.

Omega 6 and omega 3 are subsets of polyunsaturated fat that compete for absorption via the same receptor sites.  Hence, excess omega 6 and insufficient omega 3 can lead to minimal absorption of omega 3, which is critical for healthy brain function, amongst other things. 

While reasonably consistent across the year, we see a peak in the 6:3 ratio in spring at Easter and healthier lows in the ratio in summer when seafood is more abundant and overall fat intake is lower. 

Overall, a modest correlation exists between omega 6:3 ratio and energy intake (R2 = +25%).  

Our Cravings for Carbs and Fats

The table below summarises the variation in the fats and carbs, from peak to trough, across the year. 

  • Relative to the other nutrients, our body tightly regulates protein intake (both in grams and % terms).  
  • Next in line is omega 6, which appears to be tightly regulated because it is an essential nutrient.
  • At the bottom of the table, we have starch and sugar, which are optional energy sources.   
protein (%)2.7%
protein (g)2.7%
omega-6 (%)3.4%
fat (%)4.4%
energy (cal)4.9%
omega-3 (%)5.7%
omega 3 (g)7.0%
saturated fat (%)7.1%
fat (g)8.2%
carb (%)8.5%
cholesterol (mg)9.3%
saturated fat (g)9.3%
carbs (g)9.6%
cholesterol (mg/2000 cal)11%
sugar (%)19%
sugar (g)19%
starch (g)25%
starch (%)27%

Takeaway:  Our bodies tightly regulate the essential nutrients (i.e., protein, omega-6 and omega-3).  But beyond that, we’re happy to get the rest of our energy from the other foods available. 

The Most vs Least Satiating Nutrients

The table below summarises the correlation of each nutrient with overall energy intake. 

  • At the top of the table, we see that consuming a higher percentage of energy from protein is associated with eating less. 
  • For our Optimisers on a higher-fat diet, swapping their fat for fruit and vegetables that contain carbs and sugar would align with eating less.  
  • Toward the bottom of the table, we see that increasing your absolute intake of any of these nutrients aligns with eating more.
protein (%)-84%
carb (%)-22%
sugar (%)-20%
cholesterol (mg/2000 cal)-14%
starch (%)12%
omega-6 (%)19%
omega-3 (mg/2000 cal)22%
carbs (g)27%
starch (g)35%
cholesterol (mg)37%
saturated fat (%)47%
fat (%)50%
omega 3 (g)76%
saturated fat (g)79%
sugar (g)79%
fat (g)85%
protein (g)87%

By now, many of you are probably thinking, “But correlation doesn’t equate to causation.”  This is true; however, these observations from the seasonal data also align with our satiety analysis and large swathes of research.

A higher protein percentage aligns with eating less, and swapping some fat for whole-food carbs from vegetables and non-starchy vegetables will increase satiety and help you eat less.

Summary: Navigating Modern Food Environments

  • While various camps demonise one of these energy sources, there are no single energy sources that we need to fear.  We need to get our energy from somewhere. 
  • The problem comes when we separate the energy source and stick them together, like a modern Frankenstein food creation. 
  • When we combine the various energy sources in unnatural ways in the perfect proportions to hit all our nutrient bliss points (macros and micros), resistance or moderation is useless.  We can’t stop eating these processed food creations.

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