At one time or another, you have almost certainly stepped on a scale to check your body weight. But relying on scales to tell you if you’re at a healthy body weight can be frustrating. Understanding what the scale does and does not tell you will help you keep the scale’s information in perspective.
As we can see from the above graph, the number you see on your weight scales doesn’t always reflect what’s happening to your body fat. As discussed in our earlier blogpost, to gain or lose 1 kg of fat you need to be in a 7,000 kcal surplus or deficit. This can only be achieved over a long period of time as fat mass changes at a slow rate.
You may, however, notice fluctuations on your weight scales day to day and even hour to hour. We now know these fluctuations can’t be changes in body fat (1kg of fat = 7,000 kcals), so let’s now consider the other contributing factors, as outlined below.
Meal Timing and Size: a change in meal timing or size, for example, a later dinner or late-night snack, even if you were to eat the same calories overall throughout the day, will likely cause a spike in body mass. This is because your body is still digesting the food when your step on the scales.
Carbohydrate Intake: Carbohydrates are your body’s fuel source, when consumed, they are stored in your muscles and liver, much like the petrol tank in your car, ready for use at a later time. Every 1g of carbohydrate stores with 4g of water and as such, even if your overall calorie intake is equal, a higher carbohydrate meal will result in a high spike in body mass (or similarly, a low spike if it’s a lower carb meal). Remember, this isn’t body fat changing, it’s just ‘noise’ or natural fluctuations. This goes to explain why people who eliminate or drastically reduce carbohydrates see a rapid decrease in body mass followed by a plateau. It’s not body fat they’re losing but carbohydrate and water stores, which return once they revert back to their previous diet.
Food in transit: if you’re constipated or haven’t been to the toilet (including urination) the scale will increase.
Salt (sodium) intake: a higher than normal salt intake on a particular day can cause the body to retain more water.
Other factors can include recent heavy exercise sessions, stress, sleep, illness and for women; menstrual cycles. Calorie deficit is essential when trying to lose body fat however patience is required. Don’t get too excited when the scales go down, or too distressed when they go up. It’s the trend over weeks and months that is important. Weigh yourself to collect data, not to judge yourself or demonise certain foods.