You don't need to restrict fat intake on a low-carb diet to lose weight. But if you're worried about heart health, you may want to include leaner meats and healthier fats on your weight-loss plan. Before starting your low-carb, low-fat diet, consult your doctor to discuss safety and make sure it's the right fit for your health needs.
Low-Carb, Low-Fat Diet Basics
Your doctor can help you determine how many carbs you should eat each day, but it generally ranges from 20 to 50 grams a day. This low-carb intake gets your body into a state of ketosis, which happens when your body doesn't have enough carbs to burn for energy and is forced to burn fat stores instead. You'll increase your carb intake to 50 to 150 grams once you've lost much of the weight and transition to your maintenance diet.
Not all carbs are counted on many low-carb plans. Instead, "net" carbs are used, which refers to the carbs your body digests -- total carbs minus the fiber or sugar alcohol.
A low-fat diet typically restricts total fat intake to 30 percent of calories or less. For example, if you're on 1,800 calories a day, you'll get 540 calories from fat or about 60 grams of fat a day. When restricting both fat and carbs, most of your calories come from lean sources of protein and non-starchy veggies.
Keep It Low-Fat With Lean Protein
Naturally carb-free, animal proteins are usually the center of your meals on a low-carb diet. When restricting fat too, most of your animal proteins need to be lean choices. That means sirloin steak instead of porterhouse and pork chops instead of bacon. Chicken and turkey breast without the skin and egg whites instead of whole eggs also make good lean protein choices. Most fish and shellfish are very lean, with the exception of fatty fish such as salmon, tuna and sardines. However, these fattier fish are a source of omega-3 fats, which are essential, promote health and reduce risk of heart disease and certain types of cancer. Those who prefer meatless meals can choose from tofu and some soy meat products. Soy chicken, hot dogs and meat crumbles, for example, are low in fat, but have 1 to 3 grams of net carbs per serving.
Non-starchy vegetables add bulk to your meals and keep you feeling full. These veggies are low in carbs and naturally fat-free. Good ones to load up on that will cost you 1 gram of net carbs or less include bok choy, Chinese cabbage, raw celery, endive, button mushrooms, radicchio, daikon root and baby spinach. Non-starchy veggies with 1 to 5 grams of net carbs per serving include 1/2 cup of cooked broccoli or cauliflower, six pieces of fresh asparagus, 1/2 cup of red cabbage or kale, 1/2 cup of sliced cucumber and 10 cherry tomatoes.
Certain fruits may also fit your plan, including 1/2 cup of cooked pumpkin, which has 5 grams of net carbs, or 1/2 cup of black raspberries, with 4 grams of net carbs.
It's OK to Include Healthy Fats
Fats, oils, salad dressings, cheese, nuts and seeds, while low in carbs, are high in fat and may need to be limited for you to stay within diet guidelines. The low-fat diet guidelines suggest you limit fats such as butter and vegetable oils to 1 tablespoon a day. Low-fat cheese may make a good option, but be sure to read the food label to track your carbs. Nuts and seeds are a healthy source of fat -- high in unsaturated fats -- and have 1 to 3 grams of net carbs per serving. But, you might need to limit your intake of nuts to a few times a week to keep fat intake low.
With restrictions on both fat and carbs, the bulk of your calories comes from protein. Excessive protein intake can be bad for your health. If you're on an 1,800-calorie diet getting 30 percent of calories from fat and only 20 grams of carbs, that means you'll need about 300 grams of protein to meet your calorie needs. Consuming 200 to 400 grams of protein a day may exceed your ability to metabolize it properly, according to a 2006 report published in the International Journal of Sport Nutrition and Exercise Metabolism. Too much protein leads to elevated amino acid and ammonia levels, and may even cause death.
In addition to making the diet easier to follow, adding a little more fat to your plan may help better balance the calories and decrease your risk. If you do feel you need to restrict both carbs and fat, consult with a registered dietitian for help designing a safe and effective meal plan.
- New England Journal of Medicine: Weight Loss With a Low-Carbohydrate, Mediterranean or Low-Fat Diet
- Harvard School of Public Health: Low-Carbohydrate Diets
- American Journal of Clinical Nutrition: Low-Carbohydrate Nutrition and Metabolism
- Department of Developmental Services State of California Health and Human Services Agency: Diet Manual
- Atkins: Carb Counter
- Atkins: What Are Net Carbs?
- International Journal of Sport Nutrition and Exercise Metabolism: A Review of Issues of Dietary Protein Intake in Humans