Start searching for information about a vegan diet, and you’ll quickly uncover two (alleged) benefits of an animal food-free diet—at least according to the so-called dietary experts:
- Fat consumption. A vegan diet makes it easier to stay within the 25% to 35% of daily calories from fat that dieticians recommend. Supposedly, you’ll be eating healthier unsaturated fats from avocados, nuts and vegetable oils, so you’ve got that going for you—if you believe fat is evil.
- Weight loss. According to conventional nutritionists who’ve reviewed vegan diets, you are “likely” to lose weight, because you’ll be eating fewer calories, while consuming more fruits, veggies and whole grains. Thanks to that daily caloric deficit, “You’re bound to shed the pounds,” as U.S. News & World Report’s Health website phrased it.
We’ll deal with the fat intake assertion in a moment, but let’s first discuss losing weight on a vegan diet.
The assertion that weight loss is inevitable on a diet that delivers a daily caloric deficit—eating fewer calories than your body needs to maintain its basal metabolism and normal activity levels—is correct. It’s called starvation, and from famines in Africa to horror stories of concentration camps, there’s no shortage of imagery to visualize the end point of a “caloric deficit diet.”
That’s because when the body is deprived of the energy sources (and protein intake) it needs to function properly, body tissues are catabolized to make up the deficit. Yes, that involves using up stored subcutaneous fat, but it also includes the breakdown of muscle tissue, which is why famine victims appear to be wasting away.
Because they are.
Do they lose weight? Heck, yeah.
Is it healthy? Absolutely not.
Weight management is important for a variety of clinical (and aesthetic) reasons, but the way to do it doesn’t involve depriving yourself of needed calories—even a relatively small deficit—over time. In fact, that’s the exact and specific cause of “yo-yo-dieting,” a syndrome way too many overweight people have endured: You starve yourself for weeks, maybe months, until you lose a lot of weight (keep in mind, the loss is both fat and muscle tissue).
Then, after finally reaching a more desirable weight, you resume “normal” eating patterns and calorie intake. What happens?
Since you’ve lost significant muscle mass, your metabolism is slower and you’re burning fewer calories at rest. So the resumption of your previous diet means you regain the lost weight—with a vengeance. Now, the next time you try to lose weight with restrictive dieting, it’s much more challenging, and the yo-yo process repeats itself with even worse results.