Ask the Diet Doctor: The Case for Carbs
Q: How can I tell if I need to eat more carbs?
A: People often connect feelings of fatigue and brain fog with the need to eat more carbohydrates. These are not necessarily symptoms of lack of carbs but more a sign of insufficient total calorie intake in general. You often will hear that your brain runs on glucose (a.k.a. sugar) and that this is why you need to eat a higher-carbohydrate diet. But I've discussed in a previous article how this is more metabolic fairy tale than truth. It is completely safe to cut out carbs and rely on fats alone for fuel, since our bodies do a very good job of making the sugars it needs or finding alternate energy sources. For example, when you drastically reduce or eliminate carbs from your diet, your body is able to make sugar to store as glycogen.
While the question of "How many carbs should I eat?" is always at the top people's minds, it is important to realize that everything in your diet is relative to the amount of total calories you are eating. Because of protein's key role in enhancing feelings of fullness and in growth and maintenance of muscle, I always set aside calories to meet optimal protein needs first before setting carbohydrate needs. Let's look at an example on how to set your starting calories, protein, carbs, and fat levels if you want to lose weight. (Here, more on cutting calories for weight loss.)
RELATED: The Best Carbs for Weight Loss
Calories = Body weight x 12
Protein = 1 gram per pound
Carbohydrates = 0.9-1.25 grams per pound body weight
Fat = The remainder of your calories (Note: There are 9 calories per gram of fat while protein and carbohydrates both contain 4 calories per gram)
So for a woman who weighs 140 pounds:
Calories = 1,700 (1,680 rounded up for ease of calculation)
Protein = 140 grams
Carbohydrates = 140 grams (using 1g/lb)
Fat = 64 grams
The easiest way to put this plan into play (and to find out how many carbs you should eat to lose weight) is to use a food log app like MyFitnessPal (my favorite); enter your calorie, protein, carbohydrate, and fat targets for each day; and do your best to hit these targets.
At this level of calories and carbs, both are restricted but not to the point where you should experience any signs of fatigue, brain fog, or any other miserable symptoms people generally complain of while dieting. Follow this plan for two to three weeks and see how your body responds. If you are not losing weight, then don't lower your calories but first add some high-intensity exercise (like interval training) to your workout regime, aiming for four hours of total exercise per week. Do this for another two to three weeks. If you need to elicit greater weight loss, then remove about 100 calories (5 grams of fat and 15 grams of carbohydrates) from your daily diet.
Continue in this fashion, only making adjustments if your weight loss stalls and always opting for adding activity over restricting your calories. Never go below a calorie level of 10 times your body weight.
I find most of my female clients need to eat more calories and eat more carbs per day when starting a weight loss diet-due to the urge to restrict everything to elicit weight loss, they often start out too low. You may be looking at these numbers and thinking this is too many calories and too many carbs per day to lose weight. It isn't. The key is to be into your weight-loss plan for the long haul. Starting with your calories and carbs a little higher than you traditionally would will give your more room for calorie restriction later in your diet when your weight loss plateaus. (Luckily, if that does happen, we've got you covered with these plateau-busting strategies for the gym and for your diet.