Research from Harvard School of Public Health investigated what would happen to people who eat a 1500-calorie low fat diet (1800 calories for men) compared to an 1800-calorie low carb diet (2100 calorie for men). The findings were that the higher calorie low carb dieters lost more weight than the lower calorie low fat dieters. A third group was studied who consumed a 1500-calorie (1800 calories for men) low carb diet and these people lost the most weight.
Another study looked at people on a calorie matched low carbohydrate or low fat diet, the food ratios were as follows:
• Low-fat: 60:20:20 (carbohydrate:fat:protein)
• Lower-carb: 45:35:20 (carbohydrate:fat:protein)
Women eating the low carb diet lost an average of 3.4 lbs (1.5 kg) more than the women eating the low fat diet (an average of 19.6 lbs v 16.2 lbs). Even the low carb diet was still fairly high in carbohydrates and could have been reduced further to maximise weight loss.
Reducing carbohydrate usually means an increase in protein and fat. But most people fear eating too much fat because they think it will make them fat (remember 1g of fat contains 9 calories) and get advised against eating too much protein as it damages the kidneys and affects bone health. Both of these points are contentious issues and should be discussed in a separate article but suffice to say that a higher protein diet (43% carbohydrate, 33% protein and 22% fat) was more favourable in terms of weight loss when compared with resistance exercise to a conventional diet (53% carbohydrate, 19% protein and 26% fat) and exercise. Furthermore the prestigious Journal of the American Medical Association reported that a low glycemic load (GL) diet helps to reduce insulin, triglycerides and aids weight loss in overweight and obese people.
Taking in too few calories can be as detrimental as eating too many. Restricting calorie intake can cause you to lose muscle and bone density and can affect import hormone function such as the thyroid hormones. Having said that calorie guidelines may be set too high and by reducing calories to a lower but still sufficient level can aid weight loss. In order to work this out Jonny Bowden describes multiplying your target weight in pounds by 10 to get the rough number of daily calories you need to consume. For example if you want to be 150 pounds (68kg) eat roughly 1500 calories a day with only a low proportion of these calories coming from carbohydrates (40% carbohydrate, 30% protein and 30% fat).
How do you do this?
For some of you working out calories and ratios of food can be too complicated, so how do you work out a good weight loss diet?
Aim to eat 1 portion of animal protein at lunch and dinner such as a fillet of fish, a chicken breast, a home made turkey of beef burger, this will give you between 200-300g of protein which is sufficient. If you are vegetarian you will need to think about eating some eggs, or fish or tofu and combine some whole grains with beans, legumes and nuts. Aim to eat lots of non-starchy vegetables such as broccoli, cabbage, onions, asparagus, but few if any starchy vegetables such as potatoes, sweet potato and corn. Aim to eat a couple pieces of low GL fruit per day such as apples, pears, plums or berries and also eat some nuts, seeds, beans and legumes, but ditch the bread, pasta and other starchy grains. If you like some grains eat small servings of brown rice or quinoa.
Use smaller plates and divide your plate into one half and 2 quarters. The half should be full of non-starch vegetables, a quarter should be full of a good protein source such as fish or chicken and a quarter can be full of a small serving of sweet potato, quinoa or beans.