There’s a reason why Paleo is so strongly associated not just with food, but also with a particular philosophy about working out: if you’re talking about reaching our genetic potential as human animals, diet and exercise really go hand-in-hand. But what if you can’t exercise?
First of all, it’s worth re-assessing that “can’t.” By “can’t” do you really mean “I don’t want to make it a priority because Halo 4 is more fun?” Or do you really mean “I don’t want to start because I’m afraid of the weightroom?” A huge number of people who “can’t” exercise really can; they just don’t choose to for one reason or another.
But there are some cases where, for one reason or another, exercise is just not going to happen:
- Some people have a very good reason for prioritizing other things above exercise – yes, it’s ultimately a matter of priorities, but some things are a higher priority than your workouts and that’s OK.
- Some people have chronic diseases that make exercise difficult or impossible – fibromyalgia, chronic fatigue syndrome, or Lyme disease, to name a few.
- Some people have injuries that temporarily prevent them from exercising, but they still want to keep losing weight.
Between one thing and another, there are several perfectly reasonable situations that might make exercise difficult or impossible. But non-exercisers of the world, take heart: yes, you can still lose weight without breaking a sweat.
Diet Beats Exercise for Weight Loss
This meta-analysis looked at studies of diet only, exercise only, and diet + exercise. While all three of the interventions resulted in some weight loss, exercise provided, on average, a 0.3 kg (.66 pound) advantage over diet alone.
Not even one pound. Of course, that’s in lab studies, not the real world, but the point is that diet, not exercise, is responsible for the vast majority of weight loss.
To break it down even further, we could look at a very simple (almost too simple, but good enough for most of us), model of what causes weight loss.
- Creating a calorie deficit
- Making sure that the calories you do eat are used for energy, rather than stored as fat.
The first is a math problem; the second is hormonal (this is where things like insulin come in).
You can accomplish both of these things with diet or exercise, or (best of all) a combination of both. But if you have to pick just one, diet is the way to go.
Diet vs. Exercise: Calorie Deficit
300 calories take half an hour to run off and 5 minutes to eat. There’s just no competition. You could drive yourself into the ground with two-hour runs every day, wrecking your knees and social life in the process, and you would still be able to undo all of that hard work in one dinner.
Does it help to “burn off” some of those calories by exercising? Sure, it’s nice to have that extra cushion. But exercising in order to “burn calories” is a whole lot of pain for a very tiny gain.
What about your metabolism? There’s a common truism that exercising is beneficial for weight loss because it preserves muscle mass, and muscle burns more calories than fat even at rest, so muscle-building exercises assist weight loss by raising your metabolism.
It’s very true that exercise preserves lean mass. This study tested the effects of exercise only (with no diet restrictions) on weight loss in overweight men and women. The researchers concluded that exercise could help reduce the loss of lean tissue by about 2.6 pounds in men and 1 pound in women. The problem is that 1 pound of muscle only burns about 7 calories per day. So that’s 7 extra calories for women, and 18.2 for men. Women can now eat an additional strawberry per day, and men can eat an additional one-half cup of broccoli. That’s nice if one strawberry is going to make or break your diet, but it isn’t terribly significant.
The bottom line: exercise as a “calorie-burning activity” is overrated. Calorie deficits are created in the kitchen, not at the gym.
Diet vs. Exercise: Hormones
It’s one thing to say that diet beats exercise for creating a calorie deficit. But what about those perky hormones? The benefits of exercise for weight loss aren’t really about “burning calories;” they’re about hormonal improvements.
For one thing, exercise improves insulin sensitivity. This effect, more than any calories burned during the workout itself, might be the main reason why exercise is such a powerful therapy for weight loss. Exercise is a powerful therapy for any kind of carbohydrate intolerance that might be sabotaging your weight-loss efforts.
There’s really no replacement for this, but you can “correct” for it to a certain extent with diet by using a little more caution with carbs. If you tolerate carbohydrates well – great! But a completely sedentary life might reduce your carb tolerance; just be aware of how much you can and can’t handle.
Exercise also has many other hormonal benefits: effects on hormones like leptin and ghrelin (which regulate appetite), and stress reduction, just to name two. But again, as the studies of diet vs. exercise in the real world show, these are really bonuses, not essentials. There are other ways to manage appetite and stress (for example, by meditating, journaling, or creating stress management routines); you don’t have to exercise.
Losing Weight with Diet Only
As you can see, it’s perfectly possible to create both calorie deficit needed for weight loss, and the right hormonal conditions to use calorie properly, without ever breaking a sweat. But it does take a little tinkering. Specifically:
- You will need to be very mindful of your food intake. Since so many of the conditions that prevent exercise also cause other kinds of stress, pay special attention to stress-eating, eating out of boredom, or using food as an emotional crutch.
- You may find it helpful to restrict carbs a little more, depending on how you personally react to carbs.
- Adequate protein is a must. Your lean tissue is already suffering from the lack of exercise; don’t make it worse by skimping on the protein!
Doing all these things will help you lose weight, but they still won’t get you the health benefits of regular exercise (which are impossible to overstate). Losing weight and improving your health are two completely different things: you can drop a lot of scale weight without ever seeing any health benefits, and you can improve your health dramatically without any change on the scale. But for the people who can’t exercise, for whatever reason, then yes: it is possible to lose weight without it.
It’s also worth looking at it this way: Paleo + exercise is ideal. But Paleo without exercise sure beats no Paleo and no exercise. Health is not a yes-or-no question. Even if you can’t achieve total perfection, you can still take significant steps toward your health goals by going one step at a time – so if diet is all you can do at this point, it’s a lot better than nothing at all.