FatCalc

Realistic Weight Loss Goal Calculator

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Realistic Weight Loss GoalCalculate Energy & Time to Weight Loss.
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How much weight is realistic for you to lose and how many should you be consuming?

Use this calculator to find a realistic weight loss energy deficit plan that's right for you. You choose how much you want to weigh. The calculator will generate a table that lists daily energy intakes along with the time it would take you to reach your weight goal for each of the intake levels.

About the Calculations

Calculations incorporated into this app are based on the model developed by Kevin Hall, Ph. D., and a team of researchers at the National Institute of Health. It is a much more accurate model in determining energy expenditure and energy requirements for the purpose of weight management. It challenges the 3,500 Calories per pound rule by taking into consideration the physiological changes that take place during weight loss. This includes changes in body fat, muscle mass, the thermic effects of feeding, glycogen levels and sodium intake.

Your TDEE (Total Daily Energy Intake) and RMR (Resting Metabolic Rate) are also calculated. TDEE is the total amount of energy your body burns daily and is equivalent to the amount needed to maintain your current body weight. Eat less than that amount and you will lose weight. Your RMR is the amount of energy your body burns while at rest. RMR is factored into TDEE.

The calculator also calculates your body fat percentage based on your BMI (Body Mass Index) using regression equations published in a paper by Jackson et al. Although not as accurate as other popular body fat measurement methods, it nonetheless gives a ball park estimate for the purposes of weight loss calculations.

Instructions

Enter your body parameters, physical activity level, your current or starting weight and your weight goal. If you don't know your physical activity level, click the Estimate button to calculate an estimation. It will pop up a form where you select from activities at work and during your leisure time.

Click Calculate to generate a table of daily energy intake levels vs time to weight goal. Consult a doctor for guidance and support if you are considering a diet of less than 1,000 Calories (4200 kJ) per day. Food group targets and nutrient recommendations will not be met below that level.

Related Sites:

References:
  1. Quantification of the effect of energy imbalance on bodyweight.
    Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA.
    Lancet (2011 Aug 27) 27;378(9793):826-37.

  2. The effect of sex, age and race on estimating percentage body fat from body mass index.
    Jackson et al.
    International Journal of Obesity (2002) 26, 789–796

  3. A new predictive equation for resting energy expenditure in healthy individuals.
    M D Mifflin, S T St Jeor, L A Hill, B J Scott, S A Daugherty, Y O Koh
    The American Journal of Clinical Nutrition, Volume 51, Issue 2, February 1990, Pages 241–247