The targeting and restriction of specific energy foods — protein, fat and carbohydrates — have formed the backbone for the latest dietary approaches to significantly reduce weight, shed fat and retain lean tissue. Restrictive energy diets such as low or no carbs, high or low fat and generally moderate to high protein have been meticulously researched for their upside and downsides.
No diet is perfect
Most dietary intervention should lead to some short-term weight loss, but it appears that no one diet stands out in terms of keeping the weight off once normal eating patterns and preferences are restored. Any restrictive diet will not support good health and well-being as there are some minimum levels that are required for the body and metabolism to function well and not create imbalances that lead to adverse symptoms and poor performance.
Low-carb diets such as the keto are popular at the moment and stem from its use as a medical treatment to control seizures in epilepsy patients in the 1920s. Rapid weight loss was noted and this formed the basis for the Atkins diet highly lauded around 2000. Atkins is a phased diet with almost no carbs being the protocol for only a few weeks and then high-fibre carbs are slowly added. Many people only grasped the first phase and tried to hang in there. Short-term weight loss can be significant if you can stay with it but the short- and long-term effects of high-fat, low-carb and protein bring with it a number of health hazards.
High fat is undoubtedly a cardiovascular risk and this is exponentially greater if you don’t choose your fats well. Seed oils, soy, safflower, sunflower, corn, peanut and canola are right out along with trans fats and margarine. Fatty acids in the intestine feed bacteria that cause the obesity strain bacteria Firmicutes to dominate and these cause increased gut permeability along with increased fatty acid absorption and improved efficiency in energy harvesting.
We need to eat prebiotic foods such as vegetables, sweet potato, chickpeas and oats to enrich the bacteria called bacteroidetes and not Firmicutes that feed on fat. It is also seen that obesity, which is associated with the abundance of Firmicutes, leads to an overall decrease in metabolic diversity, which alters our ability to switch between energy sources to keep our energy up and perform to our potential. Behaviour Brain Research Journal showed diets with higher fat content impaired hippocampus-dependent memory, even when hypertension and obesity are absent.
Don’t ditch the carbs
Research also indicates that the brain and heart need 65g of carbohydrates a day to maintain normal function. This is five times more than recommended on a keto diet. Long-term very low-carb diets are more likely to cause depression, foggy thinking, irregular heartbeat, low energy and fatigue despite the belief they provide more energy.
High protein intake of more than 2.2g of protein per kilogram of body weight is not aligned with increased muscle and performance. Excess protein will convert to glucose, which is not the plan and overloads the kidneys with nitrogen excretion. More and more urology departments are seeing athletes with kidney infections, kidney stones and renal problems.
Keto diets force the body to use fat as the primary fuel instead of glucose. When only fat is available, fatty acids are converted into ketones and used as cellular energy. In fact, the cell works well on ketones but it also comes with many costs.
Today’s weight loss keto diets are the descendants of low-carb diets such as the Atkins diet and focus on dairy, eggs and meatier meals rather than vegetables, grains and fruit. There is no real dietary plan although being vegetarian does not make it easy, and other than familiarising yourself with the carb content of foods, you set off on your own journey eating whatever protein and fat foods you fancy and in any portion.
The theory is that using ketones as energy and not glucose omits a reliance on the major energy hormone manager, insulin, which also affects appetite. Much of the reasons for weight loss are not clearly understood as what we expect is that in the absence of insulin, fat can get out of fat cells but not get in.
A comparison published in the Journal of American Medicine (JAMA) in 2014 of several popular diets concluded with the same result as recent researchers who compared diets head-to-head. No particular diet stood out as a winner for long-term weight loss although any strict dietary practice supports some weight loss. The journal JAMA also reported no significant difference in weight dropped in their managed diets manipulating energy nutrients.
Keto diets as well as Atkin’s do cause large weight loss in the first month, mainly water weight as carbohydrates store water to stop the body becoming too glucose-loaded. Once this is lost, it is about switching into fat metabolism rather than relying on carbohydrates.
Ketogenic diets also tend to cause more calcium to be lost in the urine as high protein and fat cause a more acidic body fluid, which can lead to a decrease in bone density over time and increase the risk of osteoporosis.
Keto diets are not endorsed by dieticians who must proceed with good practice aligned with health risks and success and sustainability in the long term. There is obvious concern about high levels of saturated fat and cholesterol intake as well as inflammatory seed oils used in cooking as they do not line up well with current health guidelines. Some of this is genetically pre-determined as we now look more closely at DNA and risks associated with overconsumption of fats and carbohydrates affecting insulin.
Another popular item to enter the keto and quick fix diet arena is bullet-proof coffee taken as a breakfast replacement. Simply add 1-2 tablespoons of butter to coffee to keep you full until lunch and energised without taking carbs. Butter, like coconut oil, is a medium chain fat, which breaks down a little differently to normal fats and travels to the muscle to be used as energy rather than broken into fat microns and transported via lymph to the liver for processing and more likely to be stored. How clever is the body?
It is not a match made in heaven, coffee and medium chain fats, as it may well trigger stress hormones and it is on the whole, high in calories and not dissimilar to a meal but short of nutrient density. It doesn’t tend to carry you through the morning either and may well lead to squeezing in another meal, while overdoing total ideal fat intake over the day. Would I recommend it? I would stick with an omelette or nutrient-dense smoothie.
If you are considering trialling a diet, I would check with your GP before forcing your body to make a sudden switch or trying diets that can directly put you at further health risk even if it worked for weight loss.
— The writer is a clinical nutritionist at Emirates Integra
