Do low-carb diets promote a healthy heart?

Melanie Thomassian Health Pro
  • I absolutely detest the culture of "fad" dieting that is so prevalent today. In America, it is estimated that 45% of women, and 30% of men diet to lose weight.


    Over the years, various diets have come and gone again, but a concept that has remained for some time is low-carb eating. Supporters of low-carb diets often claim that more weight loss can be achieved with this regimen. While this often is true initially, studies comparing low-carb versus low-fat diets have found that after 12 months there was no difference. Another study found that the weight loss achieved is associated with the duration of the diet and restriction of energy intake, but not with restriction of carbohydrates as some supporters suggest.

    Add This Infographic to Your Website or Blog With This Code:


    Four factors contributing to weight loss with low-carb diets:

    • 1. Loss of water weight. Severe restriction of carbohydrates leads to glycogen stores being depleted, causing an excretion of bound water, therefore weight loss.
    • 2. Decreased appetite. The ketogenic nature of the diet leads to appetite suppression.
    • 3. High protein-content. Foods rich in protein are highly satiating (feel fuller for a longer period of time), and therefore reduces food intake.
    • 4. Reduced calories. Carbohydrate foods usually provide a very large proportion of a person's diet, but on a low-carb diet such foods are limited, hence resulting in severe calorie reduction.

    The American Heart Association has consistently expressed concern that the high-fat content of low-carb plans may increase the risk of heart disease in long term followers.


    Recent study results

    A small study recently published in the journal Hypertension, found that low-fat diets are more effective in preserving and promoting a healthy cardiovascular system than low-carb diets.

    Researchers discovered:

    • Reduced flow-mediated dilation in the arm artery in participants who were on the low-carbohydrate diet (this is an early indicator of cardiovascular disease).
    • On the other hand, flow-mediated dilation improved significantly in participants on the low-fat diet, suggesting a healthier artery that is less prone to developing atherosclerosis.
    • Reduction in brachial artery flow-mediated dilation was noted on the low-carb diet.
    • Low-carb diets were found to have significantly less daily folic acid than low-fat diets (folic acid is thought to be helpful in reducing the likelihood of heart disease).

    Larger long-term studies are needed to fully assess the cardiovascular risk factors or any adverse effects. Without this information, it is my belief that low-carb plans should not be recommended.

    What is a heart healthy diet?

    A balanced, healthy diet combined with exercise is still the most effective and safe long-term way to lose weight.

    • Reduce the calorie content of your diet by substituting low calorie foods in place of high calorie foods. For example, switch from whole milk to semi-skimmed, use olive based spreads rather than butter, or choose lean cuts of meats rather than fatty burgers, and sausages etc.
    • Create a small deficit of just 250-500 calories each day, which will help you lose 1-2 pounds over the course of a week, which is considered safe and healthy weight loss.
    • Exercise regularly by aiming for 30 minutes of moderately intense activity at least 5 times each week (e.g., walk, swim, bike, or take an aerobics class).
    • Reduce your portion size by about 25% of what you currently eat. If you habitually eat too much, this may be one of the simplest options for cutting back on calories.
    • Don't forget menu planning can be an extremely useful tool for establishing a healthy balanced eating regimen for your whole family.

    Melanie Thomassian is a dietitian and author of, an online resource for credible healthy eating tips for busy people.


Published On: March 06, 2008