Low calorie diet for weight loss
Low-calorie food means reducing the total amount of calories (energy) in the food). With low-calorie food, eat about 1000 to 1400 kcal per day. The idea behind the low-calorie diet is to create a negative energy balance, i.e. you should eat fewer calories than you burn during a day, because you lose weight.
Pirozzo and colleagues compiled clinical trials that compared low-fat and low-calorie foods (Pirozzo S et al. (2003) Should we recommend low-fat diets for obesity. Obes Rev. 4:83-90). There was no difference in how much you lost weight.
Azadbakht showed, however, that a low-calorie (at least low-calorie) diet resulted in greater weight loss than a low-fat diet (Azadbakht L et al. (2007) Better dietary adherence and weight maintenance achieved by a long-term moderate-fat diet. Br J Nutr 97:399-404). In that study, those who ate low-calorie food went down 4 kg more than those who ate low-fat foods (after 14 months).
Meal replacement: health bars, meal drinks
Meal replacement is a type of low-calorie diet. One to two of the day’s meals is replaced with a meal replacement which is usually a low-calorie drink or a healthy bar. The meal replacement usually contains about 240 kcal, with a high content of protein and a low content of fat and carbohydrates. Approximately 15% of people trying to lose weight do so with the help of Levy AS and Heaton AW (1993) Weight control practices of US adults trying to lose weight. AnNInternal With 119:661-666).
Efficacy of meal replacement has been evaluated in randomised clinical trials and in total these show that meal replacement helps with weight loss; a decrease of about 2.5 kg more, compared to low-calorie diet (Heymsfield SB et al. (2003) Weight management using a meal replacement strategy : meta and pooling analysis from six studies. Int J Obes Relat Metab Disord 27:537—549). Among patients with obesity (BMI higher than 30), meal replacement resulted in greater weight loss than caloric restriction. This has been shown to be sustainable in the long term (Flechtner-Mors M et al. (2000) Metabolic and weight loss effects of long-term dietary intervention in obese patients: four-year results. Obes Reses 8:399 —402). Today, it is considered that caloric control with meal replacement is more effective than calorie-controlled normal food.
High protein meal replacement has been shown to be excellent for weight loss among people with obesity or overweight and this has been observed in follow-up after 1 year too (Keogh JB and Clifton P (2008) The effect of meal replacements high in glycomacropeptide on weight loss and markers The risk of cardiovascular disease. Am J Clin Nutr 87:1602-1605)
Very low-calorie diet (very low calorie diet)
These diets work in the same way as low-calorie diets, but, as a rule, one should not exceed 1000 kcal per day.
Anderson compiled a total of 29 studies investigating low-calorie diets and very low-calorie diets among a total of 4300 overweight/obese people. Low-calorie diet resulted in weight loss of 11.4%, while very low-calorie foods gave weight loss of 21.3% after 24 weeks. But after 2 years the difference between the groups was significantly smaller and it was blurred over time (20 Anderson JW et al. (2001) Long-term weight-loss maintenance: a meta-analysis of US studies. Am J Clin Nutr 74:579-584). This is consistent with the Lantz study, which reported that weight loss after 4 years was approximately the same for low-calorie and low-calorie diets (7.6 kg weight loss for very low-calorie diets, and 6.3 kg weight loss for low-calorie diets). Lantz H et al. (2003) A dietary and behavioural programme for the treatment of obesity: a 4-year clinical trial and a long-term post-treatment followup.j Internal med 254:272-279