Therm (EC) to Kilocalorie (nutritional)

The EC therm is defined as exactly 105,505,600 joules; the US therm is 105,480,400 joules — a difference of 25,200 J (about 0.024%). The discrepancy arose from slightly different historical BTU definitions. For residential gas billing the difference is negligible, but in large-scale energy trading involving millions of therms, the distinction can affect settlement amounts.

The UK Gas Act 1995 mandated a switch from therms to kWh as part of broader metrication. One therm (EC) equals 29.3071 kWh. The change aligned gas billing with electricity billing, making it easier for consumers to compare energy costs. Older UK customers and industry veterans still refer to therms colloquially, and wholesale gas markets continued using therms for years after the retail switch.

A typical UK home uses 500–800 therms (EC) per year for heating and hot water, equivalent to roughly 14,700–23,400 kWh. Well-insulated newer homes may use under 400 therms, while large Victorian houses with poor insulation can exceed 1,200 therms. Ofgem's energy price cap is set in pence per kWh, but converting back to therms gives about £2.50–£3.50 per therm at recent rates.

One cubic meter of UK pipeline-quality natural gas contains roughly 38.5–39.5 MJ, which is about 0.365–0.374 therms (EC). Gas meters measure volume in cubic meters, and the utility applies a calorific value correction to convert to kWh (or therms). The correction factor varies by region and season because gas composition changes depending on the source field.

The therm (EC) was once the standard trading unit on the UK's NBP (National Balancing Point) gas market. In 2020, the ICE exchange switched NBP contracts from pence per therm to pence per kWh. Continental European hubs like TTF have always traded in euros per MWh. The therm is fading from professional use but remains in legacy contracts and older billing systems.

Most weight-loss guidelines recommend a deficit of 500 kcal/day below your maintenance level, which typically means 1,200–1,800 kcal/day for most adults. A 500 kcal/day deficit yields roughly 0.45 kg (1 lb) of fat loss per week, since one kilogram of body fat stores about 7,700 kcal. Going below 1,200 kcal/day is generally not recommended without medical supervision.

Almond cell walls are rigid and resist digestion — about 20% of the fat in whole almonds passes through the gut unabsorbed. A USDA study found that almonds provide ~129 kcal per 28 g serving, not the 170 kcal on the label. Walnuts and pistachios show similar discrepancies of 5–20%. Food labels use standard Atwater factors that assume full digestibility, which overestimates usable energy for structurally intact whole foods like nuts, seeds, and legumes.

The Atwater system assigns 9 kcal per gram of fat, 4 kcal per gram of protein, and 4 kcal per gram of carbohydrate. Alcohol provides 7 kcal/g. These rounded values have been the basis of food labeling since the 1890s. Actual digestibility varies — fiber-rich carbohydrates yield fewer usable kcal because the body cannot fully break them down.

A marathon (42.195 km) burns approximately 2,200–3,200 kcal depending on body weight, pace, and efficiency. A 70 kg runner typically burns about 2,600 kcal; an 85 kg runner about 3,100 kcal. That is roughly equivalent to 35 bananas or 13 slices of pizza. Elite runners complete the distance in about 2 hours, so their metabolic rate during the race exceeds 1,300 kcal/hour.

The International Table calorie (4.1868 J) was adopted by the Fifth International Conference on Properties of Steam in 1956 and became the standard for engineering and nutrition. The thermochemical calorie (4.184 J) was standardized earlier for chemistry. Nutritionists chose the IT value because food energy intersects more with engineering standards (steam tables, heating) than pure chemistry. The 0.07% difference is negligible for dietary purposes.