Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
200 Calories is 200 Calories. Right?
“What’s that in the road ahead?”
“What’s that in the road!? A head!?”
Context is important.
Many people think weight loss is simply about cutting calories. But context counts here, too. Calories do have context and that’s what I want to explore today. Is a calorie from fat the same as a calorie from protein or carbohydrate? Depends on the context. Does day-to-day calorie monitoring make any difference if your week-to-week weight and energy expenditure are dialed in? Maybe not.
Most people (even many scientists) believe that the body composition challenge is a relatively simple equation: to lose weight you must reduce calories (either eat less or burn more), to gain weight you must add calories, and to maintain weight you keep calories constant. Calories in over calories out.
The truth is, it’s more like a complex equation where you have to factor in many other very important variables: Do I want to lose weight or just body fat? Do I want to gain weight or just muscle? How much muscle do I want to put on and how fast? What is my personal genetic “range” or limit for body fat or muscle? These are all different contexts. And these are further affected by supply (types and quantity of foods as well as frequency of meals) and metabolic demand (your relative immediate need for either energy, repair, or building). In the short-term, they are rate-limited by hormones (insulin, glucagon, epinephrine, nor-epinephrine, cortisol etc). And in the long-term the range (or limits) of possible outcomes is determined by gene expression (5’8” ectomorphs simply can’t become 275-lb body-builders, but they can be well-proportioned 165-lb men or 135-lb women.). The context can also change day-to-day. That’s where you come in as the director.
Fat burning, glucose burning, ketone burning, glycogen storage, fat storage, gluconeogenesis, and protein turnover. All of these energy-related processes are going on simultaneously in each of us at all times. But the rate at which each of these processes happens is different in each of us and they can increase or decrease (sometimes dramatically) depending on the context of our present circumstances and our long term goals. All of these contexts utilize the same gene-based principles of energy metabolism – the biochemical machinery that we all share – but because they all involve different starting points as well as different goals or possible outcomes, they often require different action plans. We can alter the rate at which each of these metabolic processes happens simply by changing what and when we eat. We can change the context.
The RD’s will tell you that protein has four calories per gram, so when you figure your daily intake, budget calories accordingly. But protein is used by the body mostly for maintaining structure and function. Yes, it can be burned as fuel, but really only as a secondary source, and even then, it must be converted to glucose to be utilized. So, depending on the need within the body, the first 10, 20 or 30 grams of protein might go towards repair and growth – not energy. Do we therefore discount those first 30 grams when we “count calories?” Depends on the context. If you don’t exercise much and eat frequently and copiously all the time, maybe most of the protein you eat will count more towards your calorie budget (since your structural protein turnover is relatively less). On the other hand, if you run yourself ragged, are under a great deal of stress (lots of catabolic hormones) and generally don’t get much protein, maybe most of that one high-protein meal goes toward repair and won’t be called upon as fuel for days or weeks. Or maybe you’re coming off an IF day. Does it really count as calories today if it isn’t burned or stored as fat? If those protein calories today go to adding lean mass (muscle) that is retained for years, do those calories count today? Then again, as muscle it does offer a potential long-term stored source of energy when gluconeogenesis is increased. See what I mean? Depends on the context.
Fats aren’t just for fuel either. They can be integral parts of all cell membranes and hormones and can serve as critical protective cushioning for delicate organs. At what point do the fats we consume stop becoming structural and start becoming calorically dense fuel? Depends again on the context. If there’s a ton of carbohydrates accompanying the fat on a daily basis, it’s pretty certain that that fat will be stored as adipose tissue sooner rather than later. That’s nine calories per gram in the tank for future use (if ever). And that’s what adds up over time when you weigh yourself. OTOH, if you’ve withheld carbs for a few days and your insulin remains low, the fats from this meal might be used quickly to provide fuel for normal resting metabolic processes.
Keep your carbs low enough long enough and you get into ketosis, a fat-burning state that creates what many now refer to as the “metabolic advantage.” In this context, fats are fueling most of the body’s energy demands either directly as fatty acids or as the fat-metabolism byproducts called ketones. To the delight of those looking to burn off unwanted fat, it gets better. The body balances the acidic effect of any excess ketones by either excreting them in the urine (in today’s $5 a gallon economy, isn’t that wasting fuel?) and by using ketones and fatty acids to create a bit more glucose for the brain via gluconeogenesis in a fairly “energy inefficient” process.
Finally, let’s look at the lowly carbohydrate and its four calories per gram. All carbs are broken down into simple sugars, and eventually (and almost always) into glucose. The primary use of glucose from all carbohydrate food is as fuel, whether burned immediately as it passes by different organs and muscles or whether stored for later use. The brain, red blood cells, and nerve cells prefer glucose as primary fuel (but don’t absolutely require it – they can use ketones). Muscles that are working hard will prefer glucose if it is available, but don’t absolutely require it unless they are working very hard for very long. If it is not burned immediately as fuel, excess glucose will be first stored as glycogen in muscle and liver cells and then, if or when these glycogen storage depots are full, it will be converted to fatty acids and stored in fat cells as fat. The things to remember about carbs and to put into context: Carbs are not used as structural components in the body – they are used only as a form of fuel; glucose in the bloodstream is toxic to humans UNLESS it is being burned immediately as fuel. (For reference, “normal” blood sugar represents only about one teaspoon of glucose dissolved in the entire blood pool in your body). That’s why insulin is so critical to taking it out of the bloodstream and putting it somewhere FAST, like muscle cells or fat cells. Moreover, humans can exist quite easily without ever eating carbs, since the body has several mechanisms for generating glucose from the fat and proteins consumed, as well as from proteins stripped from muscle tissue. For all these reasons, in the PB-style of eating, carbs are lowest priority. Unless your context includes lots of endurance activities (or storing fat) there’s little reason to overdo the carbs (USDA and RDs’ recommendations notwithstanding).
So what’s the take home message from all this? To be honest, I thought maybe you could tell me! Maybe it’s that by understanding how these metabolic processes work, and knowing that we can control the rates at which each one happens through our diet (and exercise) we needn’t agonize over the day-to-day calorie counting. As long as we are generally eating a PB-style plan and providing the right context, our bodies will ease into a healthy, fit, long-lived comfort zone rather effortlessly.
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