How To Eat: All Your Food and Diet Questions Answered: A Food Science Nutrition Weight Loss Book

Can we define “diet,” please?

The term “diet” has been converted into a pop culture catchphrase. It’s something that you “go on” to lose weight, a short term (non-) “solution.” But “diet” comes from the Latin for (we’re translating loosely here) “lifestyle,” or daily food intake; it’s not a way to eat to lose weight as fast as possible (and gain it back even faster.) It’s how you eat for life. It’s a thing you do to remain healthy. So, you want a good diet, permanently.

Why do so many diets literally ask us to eat in an imbalanced, highly limited way?

Those are not diets for life; they’re ostensibly short-term weight loss diets, though even that’s arguable. Beyond that, they’re simply not good choices: Balance is good, imbalance is bad. Really. Period.

A lot of things not consistent with balance or health can lead to rapid weight loss in the short term — a bout of flu, for instance, or for that matter, cholera! Gimmicky weight loss diets substitute severe restrictions for long-term healthful eating. They work for quick weight loss, but they’re not sustainable. Balance, on the other hand, is a high-level principle that pertains across all considerations of diet and nutrients. For example, you need sodium to live; you just don’t need as much of it as modern, highly processed diets deliver.

Is there a “diet” that leaves all the others in the dust?

It would be truer to say that we know eating patterns that beat out other diets — but as soon as we move in that sensible, defensible direction, all the pixie dust drops out of the equation; it doesn’t sound like magic. Sadly, most people are convinced they want pixie dust, no matter how many times false promises about its magical powers have let them down, and no matter how simple good eating is shown to be. Whenever we’re comparing contemporary diets, from intermittent fasting to Whole30, there are commercial interests attached. But the simple truth is that all “good” diets share the same principles: They focus on foods that are close to nature, minimally processed, and plant predominant — what we call a whole-food, plant-predominant diet.

Is quick weight loss a bad thing? A grapefruit diet, or fasting, or whatever?

If you just go on a short-term diet as so many people do, you’ll lose both fat and muscle. If you then go off the diet and gain weight back, unless you work out like a fiend, you’ll gain back mostly fat. With each of those cycles you shift your body composition more and more toward a higher fat percentage, which is a less metabolically efficient machine. Fat requires fewer calories to maintain its size than muscle does. So essentially, you create a pathway by which you need fewer calories each time to maintain fat and require ever more severe calorie restriction to lose it. In other words: Ouch.

Can I really get all my nutrients and protein from eating just plant foods?

The fact that you may not get all the nutrients you need from a dietary pattern is in no way unique to the vegan diet experience. Almost everyone who works indoors, and wears clothes, gets less than the ideal amount of vitamin D. That said, pure or strict veganism does tend to result in low levels of long-chainomega-3 fats (from so-called fish oils, though there are also plant sources) and vitamin B12. But even if a vegan needs to supplement with B12, so what? Most American diets are deficient in certain nutrients. While you’re at it, you probably ought to supplement omega-3s and vitamin D, too.