TL;DR: The Standard American Diet is NOT a high-fat diet; it is a high-fat, high-sugar diet. Excess fat, without excess sugar, can restore metabolic balance and is not associated with diseases like fatty liver or heart disease. Excess simple carbohydrates, without excess fat, can cause metabolic stress, insulin resistance, and heart disease. (about 10 min read)

Metabolic tips to reduce excess simple sugars in your diet:

• “Excess” simple carbs are carbs we eat when we’re not moving (or didn’t recently move). Pair your simple carbs with your movement to reduce stress on your liver and decrease insulin levels.

• Get adequate essential fats (like omega-3’s) from nuts/seeds, avocados, and olives to feel full.

• Keep your liver happy by staying hydrated, not raising BGLs quickly, and let your liver keep BGLs steady by avoiding simple carbs when you’re not moving.

FIRST OF ALL, we have to admit that much of what we’re told which foods are high in “sugar” and “fat” in our diets is not correct. If you google “sugar vs fat” to try to sort out their effects on your health, you’ll get a bunch of pictures of a donut vs a cheeseburger. A donut is not sugar - it is a MIX of sugar and fat (sugar from the sugar, this one is pretty obvious; and fat from oil or butter). A hamburger is not fat - it is a MIX of fat, sugar, and protein (fat from cheese, mayo, and beef; sugar from the simple carbs in the bun and ketchup; and protein, mostly from the beef.) Reducing “sugar” in your diet does mean just cutting desserts. “High-fat” diets, especially those with saturated fats like animal meats, are usually high-fat AND high-sugar diets since so many things we eat with those “fats” are simple carbohydrates (eg. the buns or beers we eat with the beef).

The “Standard American Diet” is often called a high-fat diet when it is actually a high-fat, high-sugar diet. This creates a lot of confusion when people say that the “high-fat American diet is associated with increased heart disease” because it makes it seem like a high-fat diet causes heart disease. This statement is misleading because: (1) it’s very easy to mistake association for causation. Two things can happen together often - they're associated - but that does not mean that one causes the other. This is a logical mistake we just have to look out for. (2) Calling the Standard American Diet (SAD) a “high-fat diet” implies that it is only high in fat when it is not. This is not a mistake on our part; it is either ignorance by people talking about the diet or marketing by people who don’t want us to focus on the simple carbohydrates found in a lot of processed foods.

The Standard American Diet does cause heart disease. But is it the fat in the diet? Or the excess sugar? Or both together? How do we design a “healthy” diet if we don’t know which dietary component is causing metabolic imbalance, stress, and disease? When we talk about sugar vs fat, we have to look at how sugar and fat are metabolized individually, and then what happens when we eat them together.

It is clear that the combo high-fat, high-sugar diet is causing a lot of metabolic imbalance. Does a low-fat diet restore metabolic balance, if it still has excess simple carbohydrates? Does a low-carb diet restore metabolic balance, even if it is high in fat? We can answer this question by looking at how our bodies break down, or store, fat vs sugar.

Most of the energy you have comes from breaking down fat, not glucose. Your muscles, liver, and fat cells are all involved in breaking down fat for energy, but the different cells will do this in slightly different ways.

Your muscles will break down fat to use for energy themselves; they don’t share ketone bodies with the rest of your cells. Your fat tissue will break down fat to keep you warm (shivering in brown fat) but mostly will communicate with your liver to package up fat and ship it to your liver for further processing. Your liver will burn fat and share the ketone bodies with the rest of your body. Your liver is very involved in controlling whole-body energy levels.

If our energy comes from burning fat, why do we feel tired when our BGLs drop? Welp, like most things in metabolism, the answer is a little more nuanced than just “BGLs are low”. A more accurate answer is that BGLs got low AND YOUR LIVER DIDN’T RAISE THEM BACK UP FAST ENOUGH. Your liver should be putting new glucose into the blood when levels drop. If it doesn’t, it’s because your liver isn’t functioning at its best and it’s having a hard time making glucose to put in the blood (this is one reason why alcohol makes us “hungry” - it inhibits our liver from making + releasing glucose, our BGLs fall, and we can’t bring them back up as fast as our brain wants us to.)

A well-functioning, metabolically balanced liver will put glucose into the blood (by either making new glucose from proteins/other recycled molecules, gluconeogenesis; or by breaking down the animal starch glycogen; glycogenolysis). This will keep your BGLs from dropping and stop us from feeling tired when we don’t eat simple carbs.

Stop being afraid of fat in food. This flies in the face of the “low fat” advice that dominated nutrition and diet advice since the 1980s. And we currently have an obesity epidemic in America (currently, 1 in 3 people have insulin resistance and are considered overweight or obese). So it makes sense that people who have been told to watch their weight by their doctors, and been told to cut fat out of their diet in order to do that, might be afraid of dietary fat. This advice is just wrong, though.

Most of the fat that we store in our bodies comes from carbohydrates that we didn’t need to use for energy. High BGLs are really stressful biochemically and our bodies try very hard to not let BGLs stay high. If we aren’t moving, our pancreas should release insulin that tells our other cells to pull glucose out of our bloodstream to bring our BGLs back down to safe levels. (Type 1 and Type 2 diabetics have to do a lot of work to keep BGLs from getting/staying too high or they’ll end up with damage to their internal organs.) If we aren’t moving or didn’t just move, our cells will store that glucose as fat. (If we are moving/just moved, our muscles will take glucose out of the bloodstream without insulin and store the glucose as glycogen (aka animal starch) or fat*).

If you’re trying to reduce fat stored in your fat cells it’s more effective to cut sugars out of your diet to reduce body fat than it is to cut dietary fat. There are also some essential fats that you NEED to stay alive and you have to get them from your diet (just like you need to eat enough protein to get essential amino acids, or enough produce to get essential vitamins/minerals). And if you aren’t getting enough of an essential nutrient, you’ll continue to feel hungry even if you’ve eaten “enough calories”.

BTW, have you tried to over-eat on a high-fat, low-sugar diet? Foods with fat, or fiber, or fat + fiber together (hello nuts!) make us feel full and it’s hard to overeat them. “SARAH.” you might be saying now. “What are you talking about?? Nuts are so calorie-dense! If I eat more than 1 or 2 servings of nuts in a day - while on a low-sugar diet - SURELY I will be overeating and gain weight from dietary fat!” Try it. You won’t. You will also learn something about the regulation of fat absorption across your gut when your gut is healthy, has enough fiber, & isn’t stressed from too much simple carbs (sugar). Feel free to do this experiment for a week or two and tell me how it goes. ;)

If most of our energy comes from fat, why can it be hard to lose weight that’s stored as fat? Great question. If a person is metabolically balanced and their insulin levels (or other growth factors) are not unnecessarily high, it isn’t that hard to lose fat. Remember that insulin is a growth factor and it’s higher in our blood when we are eating a lot of simple carbs (sugar) but we aren’t moving around. Insulin tells cells to get glucose out of your blood and store it. It also tells your liver not to release glucose - so your liver can’t restore BGLs when they start dropping - and it tells your fat cells not to release fat. Lowering insulin levels and increasing dietary fiber, eating a low-sugar, ketogenic diet, and/or moving around more will help restore metabolic balance and make it easier to lose fat that’s stored in fat cells.

Metabolic tips to reduce excess simple sugars in your diet:

• “Excess” simple carbs are carbs we eat when we’re not moving (or didn’t recently move). Pair your simple carbs with your movement to reduce stress on your liver and decrease insulin levels.

• Get adequate essential fats (like omega-3’s) from nuts/seeds, avocados, and olives to feel full.

• Keep your liver happy by staying hydrated, not raising BGLs quickly, and giving it a chance to practice its job of maintaining BGLs from getting too low by avoiding simple carbs when you’re not moving.