Low Carb Diet Better Than Low Fat for Weight Loss and Heart

[Nelson Vergel]

Low-carbohydrate diets and men's cortisol and testosterone: Systematic review and meta-analysis
Joseph Whittaker 1, Miranda Harris 1

Abstract
Background: Low-carbohydrate diets may have endocrine effects, although individual studies are conflicting. Therefore, a review was conducted on the effects of low- versus high-carbohydrate diets on men's testosterone and cortisol. Methods: The review was registered on PROSPERO (CRD42021255957). The inclusion criteria were: intervention study, healthy adult males, and low-carbohydrate diet: ≤35% carbohydrate. Eight databases were searched from conception to May 2021. Cochrane's risk of bias tool was used for quality assessment. Random-effects, meta-analyses using standardized mean differences and 95% confidence intervals, were performed with Review Manager. Subgroup analyses were conducted for diet duration, protein intake, and exercise duration. Results: Twenty-seven studies were included, with a total of 309 participants. Short-term (<3 weeks), low- versus high-carbohydrate diets moderately increased resting cortisol (0.41 [0.16, 0.66], p < 0.01). Whereas, long-term (≥3 weeks), low-carbohydrate diets had no consistent effect on resting cortisol. Low- versus high-carbohydrate diets resulted in much higher post-exercise cortisol, after long-duration exercise (≥20 min): 0 h (0.78 [0.47, 1.1], p < 0.01), 1 h (0.81 [0.31, 1.31], p < 0.01), and 2 h (0.82 [0.33, 1.3], p < 0.01). Moderate-protein (<35%), low-carbohydrate diets had no consistent effect on resting total testosterone, however high-protein (≥35%), low-carbohydrate diets greatly decreased resting (-1.08 [-1.67, -0.48], p < 0.01) and post-exercise total testosterone (-1.01 [-2, -0.01] p = 0.05).
Conclusions: Resting and post-exercise cortisol increase during the first 3 weeks of a low-carbohydrate diet. Afterwards, resting cortisol appears to return to baseline, whilst post-exercise cortisol remains elevated. High-protein diets cause a large decrease in resting total testosterone (∼5.23 nmol/L).

Nutr Health. 2022 Mar 7;2601060221083079. doi: 10.1177/02601060221083079.

 

[BigTex]

This is no doubt a very health diet as well as being cardio-protective and a good way to lose weight while protecting muscle mass The only problem with it is ketosis takes a long time to provide the ATP through the oxidative energy pathways needed for anaerobic exercise. Since resistance training uses the phosphocreatine system and glycolytic energy production it becomes very challenging to provide the energy needed to short duration, high intensity activity.

The other problem is if you are more into bodybuilding, type II muscle fibers which are used in this type of training are very glucose dependent. Not only do they depend mostly on glucose to provide energy in the gym, but during the process of repetitions in the 6-12 range drive glucose/amino acids/H2O into the sarcoplasmic portion of the muscle cell supersaturating it which is thought to kick off the hypertrophy process. This also causes a significant change in muscular size because of the cellular swelling (the pump).

Mauro DiPasquale was the Chief Medical officer of the now defunct World Bodybuilding Federation run by Vince McMahon of the WWE in the early 1990's. DiPasquale had all of the competitors on his Anabolic Diet which is a cyclical ketogenic diet. The federation was a total flop as the body builders appeared on stage very flat. Meaning the lack of glucose had deflated the muscle to the point they looked more like an amateur show and not pro.

Pro bodybuilders now do more of a carb cycling diet (ala Chris Aceto) going from high to lower carbs with the majority of the carb intake before and after training. Once carbs are depleted before a show they are quickly re-inflated with glucose they hours before they walk on stage. This fills the muscles without causing a spill over effect under the skin causing the muscles to look flat and not have any definition.

If you are more concerned with the cardio protective aspect of this diet and do more aerobic activity combined with weights then this is a very good diet to try. My cardiologist wants me on it but I have declined. I have done it in the past and did not like the limits of food choices. I was also a powerlifter and it is very poor for powerlifting. It will literally kill your strength levels.