Losing Weight
I find myself (often) in a familiar conversation with strangers when they ask me for dieting advice. There is a lot of it out there, but the TL;DR is: You need to eat fewer calories than you burn to lose weight, generally a calorie is a calorie when it comes to weight loss (but not overall health), and eating less calorically dense food will help you feel full and stop eating.
#1. CICO
If you're looking to lose weight, science tells us over, and over again to focus on your diet (it doesn't have much to do with exercise). It's a comforting thought that floats around out there that "calories in, calories out" or "CICO" isn't accurate. It's complicated, but CICO is mostly accurate. Michael Matthews' book: Bigger, Leaner, Stronger does an excellent job debunking this:
Technically, a calorie is the energy needed to raise the temperature of one kilogram of water by one degree Celsius. Various foods contain varying numbers of calories. For example, nuts are very energy dense, containing about 6.5 calories per gram, on average. Celery, on the other hand, contains very little stored energy, with just 0.15 calories per gram. If you added up the calories of all the food you ate in a day and then compared that number to how many calories you burned, you’d notice one of three things:
- You ate more calories than you burned. (You’ll gain weight.)
- You ate fewer calories than you burned. (You’ll lose weight.)
- You ate about the same number of calories as you burned. (You’ll maintain your weight.)
This is the first law of thermodynamics at work, which states that energy in a system can’t be created or destroyed but can only change form. This applies to all physical energy systems, including the human metabolism, which is the series of physical and chemical processes that keep us alive—namely, the production of energy as well as the creation, maintenance, and destruction of cells and tissues. When we eat food, its stored energy is transformed by our muscles into mechanical energy (movement), by our digestive systems into chemical energy (body fat), and by our organs into thermal energy (heat).
- Matthews, Michael. Bigger Leaner Stronger: The Simple Science of Building the Ultimate Male Body (The Bigger Leaner Stronger Series Book 1) (p. 95). Oculus Publishers. Kindle Edition.
# 2. Food Quality
So CICO is true in an absolute, first-law-of-thermodynamics sort of way, but doesn't address the importance of the long-term quality of the food you consume or effect food has for specific body composition goals. Matthews puts this in context in his next point:
For all its majesty, the “CICO” (calories-in-calories-out) model has feet of clay: it accounts for how much energy you’re eating and burning, but not where the energy is coming from. As critics of energy balance will often point out, this detail is vital because our body doesn’t process all calories the same way. Protein, for example, has very different effects in the body than carbohydrate or fat, which explains why some foods are more conducive to fat loss and muscle building than others (but don’t have special properties that make them “fattening” or “slimming”). CICO also neglects the nutritional dimension of eating, which must be considered for long-term health, fitness, and vitality. While it’s possible to get and stay lean eating like a 12-year-old boy on vacation, body composition isn’t a perfect barometer for health. Just as you can be slightly overweight and healthy if you eat well and exercise regularly, you can also be fit but unwell if your body is starved of key nutrients because you’ve forsaken fruits, vegetables, whole grains, and high-quality protein for cookies, chips, pizza, and ice cream.
- Matthews, Michael. Bigger Leaner Stronger: The Simple Science of Building the Ultimate Male Body (The Bigger Leaner Stronger Series Book 1) (pp. 98-99). Oculus Publishers. Kindle Edition.
I would encourage you to go read the entire book (or at least all of chapter seven which debunks diet myths).
#3. Caloric Density
Caloric density (the literal volume of food per calorie) matters too, because humans are poorly adapted to energy-dense foods. It works like this:
- You stop eating when you feel full.
- You feel full because, among many other signals, your stomach literally pushes into your other organs and your body has stretch receptors that tell your brain when that has happened.
- When you eat less calorically dense food, it takes fewer calories of food to push your stomach into your other organs.
Dr. Gregor from NutritionFacts.org also explains this well in the context of caloric density in a presentation given in 2019.
That's It
There's a bunch of other info out there that is related to health and losing weight, and it's all interconnected, but it mostly all points back to the above three points. To illustrate, below are some of the most common pieces of advice, and which points they relate to above.
- Eating the right micronutrients / supplements (#2 & #3 - helps you make sure you get a healthy balance of calories which will inevitably need to include lower calorically dense fruits and veggies)
- Tracking macronutrients (#2 - helps you make sure you get a healthy balance of calories)
- Getting enough exercise (#1 - it will affect total calories burned)
- Getting enough sleep (#1 - it will affect when you're hungry because your cells have a circadian rhythms too)
- Drinking water / staying hydrated (#1 - sometimes when you're hungry, you're actually thirsty, and this helps you eat fewer calories)
- Intermittent fasting / time-restricted feeding (#1 - helps you eat fewer calories)
- Reducing stress / yoga / tea (#1 - helps you eat fewer calories)
- Reducing alcohol / tobacco use (#1 & #2 - allows you to consume fewer, and more high quality calories)
These are all worth understanding and there's probably a book you could read about each of these topics. They'll all help you be healthier (and maybe help you lose weight?), but they're not as important as understanding the above three points.
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