Veggie Blog

Food gets most of the attention in any diet book, and the Atkins plan is no exception. The old version of this post said that many people make the mistake of ignoring exercise, and that is a fair warning. It also claimed that exercise helps your body “eliminate toxins through sweat glands and lymph systems” and that sedentary people have extreme insulin reactions to carbohydrates. Neither claim is well supported, so I have replaced them with what the official guidelines say.

Does Atkins recommend exercise?

Yes. The old post was right that critics sometimes say Atkins ignores exercise and that this is unfair. The Atkins site says that being active is important and that if you exercise regularly you will probably have a higher carb tolerance, which is the amount of net carbs you can eat without gaining weight. Atkins also tells people in the maintenance phase that activity helps them keep the weight off. Exercise supports any weight-loss plan, whether low-carb or not.

How much exercise do adults need?

The Physical Activity Guidelines for Americans advise adults to do at least 150 to 300 minutes a week of moderate-intensity aerobic activity, such as brisk walking or fast dancing. They also recommend muscle-strengthening activity, like lifting weights or doing push-ups, on at least two days each week. The first guideline is to move more and sit less. The guidelines add that any amount of physical activity has some health benefits and that activity can improve insulin sensitivity, blood pressure and sleep quality right away. That is the evidence-based way to put the old post’s point about insulin: regular activity makes the body respond better to insulin, but I did not find support for the claim that sedentary people react extremely to moderate carbs.

What are the two main types of exercise?

The old post described aerobic and anaerobic exercise. In everyday terms, aerobic exercise is steady activity that raises your heart rate, such as walking, cycling or swimming. Strength training means working your muscles against resistance with weights, bands or your own body weight. The post said that you need weights as you lose fat so you can replace it with muscle, and that you will not become a bodybuilder by doing so. It is a common view, and the guidelines do recommend strengthening work at least twice a week, though I did not find a source for the exact claim about replacing fat with muscle.

How should a beginner start?

The old post recommended asking your doctor or a qualified instructor if you have been inactive, starting slowly and learning to warm up and stretch to avoid strain. That is sound advice. It gave an example of beginning a walking program by walking four blocks, then five, then six, and that is a good model. Choose activities you enjoy, set small goals and build up. Walking, golf, tennis and dancing are all fine starting points. Our posts on moderate exercise for fitness and everyday activities that count as moderate exercise show how easy it is to fit them into your day.

Is there anything special about exercising on a low-carb plan?

A little. In the first days after cutting carbs sharply, some people feel tired, headachy or irritable, sometimes called the “keto flu.” Cleveland Clinic says these symptoms can appear two to seven days after you reach ketosis, usually ease within a week or two, and that it is best to avoid vigorous physical activity until fatigue, muscle cramps and irritability pass. Atkins guidance for health professionals also suggests getting enough salt, broth or soy sauce while net carbs are 50 grams a day or less, unless a doctor has prescribed a low-sodium diet, to avoid symptoms of the switch. So in the first couple of weeks, gentle walks make more sense than hard workouts, and you can build up as you feel better. Our guide to Atkins and ketosis explains what is going on in the body.

What should you take away?

Pair your meal plan with regular activity from the beginning, not as an afterthought. Aim for the guideline targets, work up to them gradually and talk to your doctor if you have a medical condition. Our summary of the basics of the Atkins diet shows where exercise fits in the overall plan. For more on the symptoms of the first days, see Cleveland Clinic’s guide to keto flu.